Certification terms: D

555 study terms starting with D.

555 terms

.dockerignoreA file that excludes paths from the Docker build context sent to the builder.Foundational
/dev DirectoryThe Linux directory containing device files that represent hardware and pseudo-devices, such as disks, terminals and /dev/null.Foundational
DAD TriadThe opposite of the CIA triad: disclosure, alteration, and destruction (denial) of information.Foundational
DaemonA background process that runs without an interactive terminal, typically providing a system service.Foundational
DaemonSetA Kubernetes workload object that ensures a copy of a pod runs on all (or selected) nodes.Foundational
Daily ScrumA 15-minute event for Developers to inspect progress toward the Sprint Goal and adapt the Sprint Backlog.Foundational
DAMA-DMBOKThe Data Management Body of Knowledge published by DAMA International, which defines data management knowledge areas with data governance at the center.Intermediate
Dangling DNS RecordA DNS record that points to an IP address or cloud resource no longer owned or controlled by the organization.Intermediate
DanteAudinate's widely used audio-over-IP technology that carries many channels of low-latency digital audio over standard Ethernet.Intermediate
Dark LaunchDeploying a feature to production while hiding it from users, so it can be tested with real traffic or infrastructure before release.Intermediate
Dark Web MonitoringWatching underground forums, marketplaces and leak sites for stolen data, credentials or threats targeting an organization.Intermediate
DashboardVisual display of key metrics using components sourced from reports.Foundational
Dashboard (Data Visualization)A visual display of the most important information needed to achieve objectives, arranged on a single screen for at-a-glance monitoring.Foundational
Dashboard (ServiceNow)Collection of reports, widgets and PA visualizations on tabs, shared with users, groups or roles.Foundational
Dashboard ActionsInteractivity rules in Tableau dashboards: filter, highlight, URL, go to sheet, parameter and set actions triggered by hover, select or menu.Intermediate
Data 360Salesforce's real-time data platform (formerly Data Cloud) that unifies customer data and powers analytics, AI and activation.Foundational
Data 360 SegmentAudience defined by filters on Data 360 attributes and related data, published to activation targets.Intermediate
Data AccuracyThe data quality dimension measuring how well data values reflect the real-world entities or events they describe.Foundational
Data ActionData 360 feature that triggers downstream actions such as platform events or webhooks when data conditions are met.Advanced
Data Analysis Expressions (DAX)The formula language of Power BI, Analysis Services Tabular and Power Pivot, used for measures, calculated columns, calculated tables and security rules.Intermediate
Data Analysis ProcessA structured analytics workflow; the Google Data Analytics certificate's six phases are Ask, Prepare, Process, Analyze, Share and Act.Foundational
Data Analytics in AuditingUse of data analysis tools to test entire populations, identify anomalies, and support risk assessment.Intermediate
Data AnomaliesInsert, update and delete anomalies: integrity problems caused by redundant data in unnormalized tables.Intermediate
Data ArchivingMoving data that is no longer actively used to lower-cost, long-term storage while keeping it retrievable for compliance or reference.Foundational
Data at RestData stored on persistent media such as disks, databases, backups, or cloud object storage.Foundational
Data AugmentationExpanding a training set by creating modified copies of existing examples.Intermediate
Data BlendingA Tableau technique that combines data from separate data sources at the aggregate level of the view, linked on common dimensions.Intermediate
Data BreachA security incident resulting in confirmed unauthorized access to or disclosure of sensitive data.Foundational
Data Breach NotificationLegal or contractual obligations to inform regulators, affected individuals or partners after a qualifying data breach.Intermediate
Data CatalogAn inventory of an organization's data assets with metadata, descriptions, ownership, classifications, lineage and search for discovery.Intermediate
Data CategoryHierarchical classification used to organize Knowledge articles and control their visibility.Intermediate
Data Center Bridging (DCB)A set of IEEE Ethernet enhancements, including PFC, ETS and DCBX, that enable lossless, prioritized traffic for storage and RDMA.Advanced
Data Center GPU Manager (DCGM)NVIDIA tools for monitoring, health-checking and diagnosing GPUs in clusters.Advanced
Data Center Infrastructure Management (DCIM)Software that monitors and manages data center physical infrastructure such as power, cooling, space and assets.Intermediate
Data ClassificationCategorizing data by sensitivity and value to determine required protection and handling.Foundational
Data Clean RoomA secure environment where multiple parties can run approved joint analyses on combined data without exposing raw records to each other.Advanced
Data CleansingDetecting and correcting or removing inaccurate, incomplete, duplicate or improperly formatted data.Foundational
Data CompletenessThe data quality dimension measuring whether all required data values and records are present.Foundational
Data ConsistencyThe data quality dimension measuring whether the same data agrees across records, systems and time.Foundational
Data ContractA formal agreement between data producers and consumers that specifies schema, semantics, quality expectations, SLAs and change management for a dataset.Advanced
Data Control Language (DCL)The SQL commands that manage permissions: GRANT, REVOKE and, in SQL Server, DENY.Foundational
Data ControllerEntity that determines the purposes and means of processing personal data.Foundational
Data CustodianRole responsible for implementing and maintaining the controls that protect data on behalf of the data owner.Foundational
Data DateThe point in time when the status of the project is recorded.Advanced
Data DeduplicationA storage efficiency technique that eliminates duplicate data blocks or segments, storing only one copy and references to it.Intermediate
Data Definition Language (DDL)The SQL commands that define and change database structure: CREATE, ALTER, DROP, TRUNCATE and RENAME.Foundational
Data DemocratizationMaking data accessible to non-technical users across an organization, with appropriate governance.Foundational
Data DictionaryA repository of metadata describing each table, column, data type, constraint and meaning in a database.Foundational
Data DriftA change in the statistical distribution of input data in production compared with training data.Intermediate
Data Encryption Standard (DES)Legacy symmetric block cipher with a 64-bit block and 56-bit effective key, now insecure.Foundational
Data EnrichmentAdding context, such as threat intelligence, asset criticality, user identity or geolocation, to events and alerts.Intermediate
Data Execution Prevention (DEP)A mitigation that marks memory regions such as the stack and heap as non-executable, using the CPU's NX/XD bit.Intermediate
Data ExfiltrationThe unauthorized transfer of data out of an organization to an attacker-controlled location.Intermediate
Data Export ServiceSetup feature to export all org data as CSV files weekly or monthly, manually or on a schedule.Foundational
Data Extension (DE)Table in Marketing Cloud Engagement that stores subscriber or relational data with defined fields.Foundational
Data FabricAn architecture that uses metadata, automation and integration services to provide unified, governed access to data across distributed sources.Advanced
Data FederationRunning a single query across multiple independent databases and returning combined results.Intermediate
Data Flow Diagram (DFD)Model showing how information flows through processes, data stores, and external entities.Intermediate
Data FrameAn 802.11 frame type (type 2) that carries upper-layer payloads or signals power state.Intermediate
Data FreshnessHow recently data was updated relative to expectations, usually monitored as the time since the last successful load.Intermediate
Data GovernanceThe framework of policies, roles, standards, processes and controls that ensures data is managed as an asset: secure, high quality, compliant and usable.Foundational
Data HistorianA database that collects and stores time-series process data from industrial control systems for analysis and reporting.Intermediate
Data Import WizardBrowser-based import tool for up to 50,000 records of accounts, contacts, leads, solutions, campaign members and custom objects.Foundational
Data in TransitData moving across a network between systems, also called data in motion.Foundational
Data in UseData actively being processed in memory or by a CPU, which is typically unencrypted during computation.Intermediate
Data IngestionThe process of importing data from sources into a storage or processing platform, in batches or as a stream.Foundational
Data LabelingThe process of annotating raw data with labels so it can be used for supervised training or evaluation.Foundational
Data LakeA central repository that stores large volumes of raw data in any format (structured, semi-structured or unstructured) cheaply, usually in object storage.Foundational
Data Lake Object (DLO)Storage container in Data 360 holding ingested source data before or after transforms.Intermediate
Data LakehouseAn architecture that adds warehouse features such as ACID transactions, schema enforcement and fast SQL to low-cost data lake storage using open table formats.Intermediate
Data LeakageWhen information unavailable at prediction time leaks into training, producing unrealistically good evaluation results.Intermediate
Data Lifecycle Management (DLM)Managing data from creation and storage through use, sharing, archiving and secure deletion according to policy.Intermediate
Data LineageThe record of where data originated and how it was transformed on its way to a model or report.Intermediate
Data Link Layer (L2)OSI Layer 2, which delivers frames between nodes on the same local network using physical (MAC) addresses.Foundational
Data LiteracyThe ability to read, work with, analyze and communicate with data.Foundational
Data LoaderClient application for bulk import, export, update, upsert, delete and hard delete of Salesforce records.Foundational
Data Lookup RuleRule that sets field values based on matching values in a lookup table, such as priority from impact and urgency.Intermediate
Data Loss Prevention (DLP)Technology that detects and blocks unauthorized transmission or storage of sensitive data.Foundational
Data Manipulation Language (DML)Apex statements insert, update, upsert, delete, undelete and merge that persist records.Foundational
Data Manipulation Language (SQL) (DML)The SQL commands that add, change or remove rows: INSERT, UPDATE, DELETE and MERGE (and, in some classifications, SELECT).Foundational
Data MapperOmniStudio tool (formerly DataRaptor) for reading, transforming and writing Salesforce data via JSON mapping.Foundational
Data MappingDocumenting what personal data an organization holds, where it resides, how it flows, who accesses it, and why.Foundational
Data MartA subset of a data warehouse focused on one business area or department, such as sales or finance.Foundational
Data MaskingObscuring parts of sensitive data so it remains usable for some purposes without revealing the full value.Foundational
Data Masking for AIRedacting or replacing sensitive data such as PII before it reaches an AI model or appears in outputs.Intermediate
Data MeshA decentralized sociotechnical approach in which domain teams own and serve their data as products on a self-service platform, with federated governance.Advanced
Data MinimizationPrinciple of collecting and retaining only the personal data that is adequate, relevant, and necessary for a stated purpose.Foundational
Data Model Object (DMO)Harmonized object in the Customer 360 Data Model to which data lake objects are mapped.Intermediate
Data ObservabilityContinuous monitoring of data health across pipelines (freshness, volume, schema, distribution and lineage) to detect and resolve issues quickly.Intermediate
Data OrchestrationCoordinating the scheduling, dependencies, retries and monitoring of data pipeline tasks.Intermediate
Data Over Cable Service Interface Specification (DOCSIS)The CableLabs standard for delivering broadband data over cable TV coaxial networks.Intermediate
Data OwnerSenior individual accountable for a data set, including its classification, access approval, and protection requirements.Foundational
Data ParallelismDistributed training where each GPU holds a full model copy and processes a different slice of each batch.Intermediate
Data ParsingBreaking a string or semi-structured value into components, such as splitting a full address into street, city and postal code.Foundational
Data PerimeterSet of preventive guardrails ensuring only trusted identities access trusted resources from expected networks.Advanced
Data PipelineAn automated series of steps that moves data from sources through transformations to destinations.Foundational
Data PoisoningAn attack that corrupts training, fine-tuning or retrieval data to manipulate model behavior or implant backdoors.Intermediate
Data PolicyRule enforcing mandatory or read-only fields server-side for all data sources, including imports and web services.Intermediate
Data Processing Agreement (DPA)Contract between a controller and processor setting out GDPR Article 28 obligations.Intermediate
Data Processing Unit (DPU)A programmable processor that offloads networking, storage and security tasks from the host CPU.Intermediate
Data ProcessorEntity that processes personal data on behalf of and under the instructions of a controller.Foundational
Data ProductA curated, discoverable, trustworthy dataset or service owned by a domain team and published for others to consume.Intermediate
Data ProfilingExamining data to summarize its structure, content, completeness, distributions, patterns and anomalies before using it.Foundational
Data Protection Impact Assessment (DPIA)GDPR Article 35 assessment required before processing likely to result in high risk to individuals' rights and freedoms.Intermediate
Data Protection Officer (DPO)GDPR-mandated role that independently advises on and monitors data protection compliance.Intermediate
Data ProvenanceThe documented origin and history of data, including where it came from, who created or changed it, and how.Intermediate
Data Quality (DQ)The degree to which data is fit for its intended use, judged on dimensions such as accuracy, completeness, consistency, timeliness, validity and uniqueness.Foundational
Data Quality DimensionsMeasurable aspects of data quality: accuracy, completeness, consistency, timeliness, validity and uniqueness.Foundational
Data Query Language (DQL)The SQL sublanguage for retrieving data, consisting essentially of the SELECT statement.Foundational
Data RateThe PHY signaling speed at which bits are transmitted over the air, not user throughput.Foundational
Data ResidencyRequirement or choice that data be stored and processed in a specific geographic location.Foundational
Data Retention PolicyPolicy defining how long categories of data are kept and how they are disposed of when no longer needed.Foundational
Data Security Posture Management (DSPM)Tools that discover, classify and monitor sensitive data across cloud data stores and assess its exposure and access risk.Advanced
Data SerializationConverting in-memory data structures into a format that can be stored or transmitted, and back (deserialization).Foundational
Data SiloData isolated within one department or system and not accessible or integrated with the rest of the organization.Foundational
Data SkewAn uneven distribution of data across partitions, so a few tasks process far more data and slow the whole job.Advanced
Data SkippingUsing per-file min/max statistics to skip files that cannot contain rows matching a query filter.Advanced
Data SourceA Terraform construct that reads information about existing infrastructure or external data without managing it.Intermediate
Data Source (ServiceNow)Record defining where import data comes from, such as file, JDBC, LDAP or REST, and how to parse it.Foundational
Data SovereigntyPrinciple that data is subject to the laws and governance of the country in which it is collected or stored.Foundational
Data SpaceLogical partition in Data 360 that separates data, metadata and processes by brand, region or department.Advanced
Data StandardizationConverting data into a consistent format and set of codes, such as ISO dates, country codes, units and naming conventions.Foundational
Data StewardRole responsible for data quality, metadata, and appropriate use of data according to policy.Intermediate
Data StorytellingCommunicating insights by combining data, visuals and narrative tailored to an audience to drive understanding and action.Foundational
Data StreamConfigured source connection that ingests data into Data 360 on a schedule or in real time.Intermediate
Data SubjectThe identified or identifiable natural person to whom personal data relates.Foundational
Data Subject Access Request (DSAR)Request by an individual to access personal data an organization holds about them.Foundational
Data SwampA data lake that has become unusable because of missing metadata, governance and quality controls.Foundational
Data TimelinessThe data quality dimension measuring whether data is available and current enough for its intended use.Foundational
Data TransformationConverting data from one structure, format or value set to another, by filtering, joining, aggregating, pivoting, deriving or recoding.Foundational
Data UniquenessThe data quality dimension measuring whether each real-world entity is recorded only once.Foundational
Data ValidityThe data quality dimension measuring whether values conform to defined formats, types, ranges and business rules.Foundational
Data VaultA modeling method for agile, auditable warehouses that separates business keys (hubs), relationships (links) and descriptive history (satellites).Advanced
Data Vault HubA Data Vault table that stores the unique list of business keys for a core business concept, with a hash key, load date and record source.Advanced
Data Vault LinkA Data Vault table that records relationships or transactions between two or more hubs.Advanced
Data Vault SatelliteA Data Vault table that stores descriptive attributes and their full change history for a hub or link.Advanced
Data ViewsSystem tables in Marketing Cloud such as _Sent, _Open, _Click, _Bounce and _Subscribers that hold tracking data queryable via SQL.Advanced
Data VirtualizationQuerying data in place across multiple sources through a unified layer, without physically copying it.Intermediate
Data Virtualization PatternIntegration pattern that accesses external data in real time without persisting it in Salesforce.Advanced
Data VisualizationRepresenting data graphically so that patterns, trends, comparisons and outliers can be understood quickly.Foundational
Data Warehouse (DW)A central repository of integrated, cleaned, historical data from multiple sources, structured for analytics and reporting.Foundational
Data WranglingThe overall process of discovering, structuring, cleaning, enriching and validating raw data into an analysis-ready form; also called data munging.Foundational
Data-Ink RatioEdward Tufte's principle that the share of a graphic's ink devoted to data should be maximized and non-data ink minimized.Intermediate
Database as a Service (DBaaS)Managed cloud database offering where the provider handles provisioning, patching, backups and high availability.Foundational
Database AuditingTracking and recording database events such as logins, queries, permission changes and data modifications for security and compliance.Intermediate
Database ClassApex class with methods like Database.insert and Database.update that support partial success via the allOrNone parameter.Intermediate
Database IndexA data structure that speeds up row lookups on one or more columns at the cost of extra storage and slower writes.Foundational
Database NormalizationThe process of organizing tables to reduce redundancy and prevent update anomalies by applying normal forms.Foundational
Database ReplicationThe CUCM process that copies configuration data from the publisher to all subscribers so each can process calls independently.Advanced
Database SchemaThe structure of a database (its tables, columns, types, keys and relationships), or a named namespace that groups database objects.Foundational
Database StatisticsMetadata about the distribution of values in columns and indexes, used by the optimizer to estimate row counts.Advanced
Database TableThe core relational storage object: a named set of rows sharing the same columns; formally called a relation.Foundational
Database TransactionA logical unit of work of one or more operations that must succeed or fail as a whole.Foundational
Databricks Asset Bundles (DABs)A Databricks infrastructure-as-code format that defines jobs, pipelines and other resources in YAML for versioned CI/CD deployment across environments.Advanced
Databricks Mosaic AIDatabricks capabilities for building, evaluating, serving and governing ML and generative AI on the lakehouse.Intermediate
Databricks SQL WarehouseDatabricks compute optimized for SQL analytics and BI, available as serverless, pro or classic, with Photon and intelligent workload management.Intermediate
DataflowLegacy JSON-defined CRM Analytics data preparation job using transformations like sfdcDigest, augment and sfdcRegister.Advanced
Dataflow Gen2Fabric's low-code data preparation item that uses Power Query Online to ingest and transform data and write it to lakehouses, warehouses and more.Intermediate
DatagramA self-contained, independently routed unit of data sent without a prior connection, commonly the UDP PDU.Foundational
Datagram Transport Layer Security for SRTP (DTLS-SRTP)A key exchange method (RFC 5764) that performs a DTLS handshake on the media path to derive SRTP keys.Advanced
Dataplex Universal CatalogGoogle Cloud's intelligent data governance service for discovering, cataloging, profiling, checking quality and managing lineage across data.Advanced
DataprocGoogle Cloud's managed Spark and Hadoop service, with fast cluster creation, autoscaling and a serverless Spark option.Intermediate
DataWeave (DW)MuleSoft's functional expression and transformation language for querying and transforming data between formats like JSON, XML, CSV and Java.Foundational
DataWeave FunctionBuilt-in or user-defined function in DataWeave, such as map, filter, reduce, pluck, groupBy, flatten and orderBy.Intermediate
Date DimensionA dimension with one row per calendar date and attributes such as year, quarter, month, weekday, fiscal period and holiday flag.Foundational
DAX MeasureA DAX calculation evaluated at query time in the filter context of each visual cell; it is not stored in the model.Intermediate
dbtA transformation framework (data build tool) where analysts write SQL SELECT models that run in the warehouse, with tests, docs and lineage.Intermediate
DCSyncAn attack that impersonates a domain controller to request password hashes from Active Directory via replication.Advanced
ddA Unix command-line utility used to create raw bit-for-bit copies of disks and partitions.Intermediate
DDR3 SDRAMThird-generation DDR memory using 240-pin DIMMs at 1.5 V (1.35 V for DDR3L).Foundational
DDR4 SDRAMFourth-generation DDR memory using 288-pin DIMMs at 1.2 V with JEDEC speeds up to 3200 MT/s.Foundational
DDR5 SDRAMFifth-generation DDR memory with on-module power management, two subchannels per DIMM, and speeds from 4800 MT/s.Foundational
De-identificationGeneral term for removing or obscuring identifiers to reduce the link between data and individuals.Intermediate
Dead Letter Queue (DLQ)Queue receiving messages that could not be processed after a maximum number of delivery attempts.Intermediate
Dead PixelA display pixel that stays black, or a stuck pixel that stays one color, due to a panel defect.Foundational
DeadlockA cycle in which two or more transactions each hold a lock the other needs, so none can proceed.Intermediate
Deauthentication AttackA wireless attack that sends forged 802.11 deauthentication frames to disconnect clients from an access point.Intermediate
Deauthentication FrameA management notification frame that ends authentication and association.Intermediate
Debug LEDMotherboard indicator lights or a two-digit display that show which POST stage failed.Intermediate
Debug LogRecord of database operations, system processes and errors from a transaction, captured when a trace flag is set.Foundational
Debug Mode in ProductionLeaving framework debug features, consoles or verbose diagnostics enabled on production systems.Foundational
DecapsulationThe reverse of encapsulation, in which each layer on the receiver removes and processes its header before passing data up.Foundational
Deception TechnologySecurity tools that deploy decoys, lures and fake credentials throughout an environment to detect attackers.Intermediate
Decibel (dB)A logarithmic unit expressing the ratio between two power levels; dBm expresses absolute power relative to 1 milliwatt.Intermediate
Decibel Relative to Dipole (dBd)Antenna gain in decibels compared with a half-wave dipole antenna.Intermediate
Decibel Relative to Isotropic Radiator (dBi)Antenna gain in decibels compared with a theoretical isotropic radiator.Foundational
Decibel Unit dBuA decibel unit for audio voltage referenced to 0.775 volts RMS, used for professional line levels.Intermediate
Decibel-Milliwatt (dBm)Absolute power level in decibels relative to 1 milliwatt (0 dBm = 1 mW).Foundational
Decision ElementFlow element that branches the path based on conditions evaluated in order.Foundational
Decision MatrixBusiness Rules Engine lookup table that returns outputs based on matching input values.Advanced
Decision ModelingTechnique showing how repeatable business decisions are made using decision tables, trees, or DMN.Advanced
Decision TableTable of conditions and results used by flows to make rule-based decisions without scripting.Advanced
Decision TreeA model that predicts by learning a hierarchy of if-then splits on feature values.Foundational
Decision Tree AnalysisDiagramming and calculation technique for evaluating alternative choices under uncertainty using expected monetary value.Advanced
Decision-Making TechniquesGroup methods for reaching decisions, such as unanimity, majority, plurality, autocratic, fist of five, and Roman voting.Intermediate
Declarative ConfigurationSpecifying the desired end state of a system and letting a tool determine the steps to reach it.Foundational
Decoder-Only ArchitectureA transformer that uses only the decoder stack with causal (masked) attention to generate text one token at a time.Intermediate
Decoding StrategyThe method used to choose each next token from the model's probability distribution.Intermediate
DecompositionTechnique for dividing and subdividing scope and deliverables into smaller, more manageable parts.Foundational
Decomposition TreeA Power BI AI visual that lets users break a measure down across dimensions in any order, with AI splits suggesting the highest or lowest values.Advanced
DeconflictionThe process of distinguishing authorized testing activity from a real attack when defenders detect suspicious behavior.Intermediate
Dedicated Graphics Card (dGPU)A separate expansion card or chip with its own GPU and video memory (VRAM) for graphics and compute.Foundational
Dedicated HostPhysical server fully allocated to one customer, giving visibility of sockets and cores for license compliance.Intermediate
Dedicated InstanceAWS EC2 instance that runs on hardware dedicated to a single customer but without host-level placement control.Intermediate
Dedicated Load Balancer (DLB)CloudHub 1.0 load balancer within an Anypoint VPC supporting custom domains, certificates and URL mapping rules.Advanced
Deep Learning (DL)A subset of machine learning that uses multi-layer neural networks to learn hierarchical representations directly from raw data.Foundational
Deep Link HijackingAbuse of custom URL schemes or unverified links so a malicious app receives links intended for another app.Advanced
DeepfakeSynthetic audio, video or images generated with AI to convincingly impersonate a real person.Intermediate
Default ConstraintA constraint that supplies a value for a column when an INSERT does not specify one.Foundational
Default CredentialsFactory-set usernames and passwords on applications, devices or services that are publicly documented.Foundational
Default GatewayThe router address a host sends traffic to when the destination is on a different subnet.Foundational
Default RouteThe route 0.0.0.0/0 (or ::/0 in IPv6) that matches any destination not covered by a more specific route.Intermediate
Default-Information OriginateA command that makes OSPF (or other protocols) advertise a default route into the routing domain.Intermediate
Defect RepairAn intentional activity to modify a nonconforming product or product component.Foundational
Defects per Million Opportunities (DPMO)Six Sigma metric: (defects / (units x opportunities per unit)) x 1,000,000.Intermediate
Defense in DepthLayering multiple, independent security controls so that the failure of one does not compromise the asset.Foundational
Defense Industrial Base Cybersecurity Assessment Center (DIBCAC)DCMA organization that performs DoD-led cybersecurity assessments of defense contractors, including CMMC Level 3.Advanced
Define ActivitiesProcess of identifying and documenting the specific actions to be performed to produce deliverables.Foundational
Define ScopeProcess of developing a detailed description of the project and product.Foundational
Definition of Done (DoD)A formal description of the state of the Increment when it meets the quality measures required for the product.Foundational
Definition of Ready (DoR)An optional team agreement on criteria a backlog item must meet before it can be selected for a Sprint.Intermediate
Definition of Workflow (DoW)In Kanban, the explicit shared understanding of what flow means for a team: units, start and finish points, states, WIP controls, and SLE.Advanced
Definitive EstimateA detailed, high-accuracy estimate typically in the range of -5% to +10%.Intermediate
DefragmentationReorganizing file fragments on a hard drive so they are stored contiguously to improve read speed.Foundational
Degenerate DimensionA dimension key, such as an order or invoice number, stored in the fact table with no separate dimension table.Advanced
Delay SpreadThe time difference between the first and last significant multipath arrivals of a signal.Advanced
Delayed Offer (DO)A SIP call flow in which the INVITE has no SDP, so the callee makes the offer in its 200 OK and the caller answers in the ACK.Advanced
Delegated AdministrationFeature allowing designated non-admin users to manage users in specified roles and assign certain profiles and permission sets.Intermediate
DELETE StatementThe DML statement that removes rows that match a condition from a table, logging each row.Foundational
Delimited Text FileA plain-text file, such as CSV or TSV, in which fields are separated by a delimiter and records by line breaks.Foundational
DeliverableContractually specified work product formally reviewed, agreed and signed off by stakeholders.Foundational
Delivery ProfileMarketing Cloud setting controlling the sending IP address and header and footer content.Intermediate
Delivery Traffic Indication Message (DTIM)A special TIM indicating that buffered broadcast and multicast frames will be sent after the beacon.Advanced
Delphi TechniqueStructured, anonymous, iterative method for reaching expert consensus, often used in qualitative risk analysis.Intermediate
Delta LakeAn open-source table format that adds ACID transactions, schema enforcement and evolution, time travel and MERGE to Parquet files.Intermediate
Delta Lake Time TravelQuerying or restoring earlier versions of a Delta table by version number or timestamp.Intermediate
Delta SharingAn open protocol for securely sharing live Delta Lake and other data with any platform, without copying it.Advanced
Delta Transaction LogThe _delta_log folder of ordered JSON commit files and Parquet checkpoints that records every change to a Delta table and provides ACID guarantees.Advanced
Demand ManagementSPM process for capturing, assessing and approving requests for new work before they become projects or epics.Intermediate
Demarcation PointThe point where the service provider's network responsibility ends and the customer's begins.Foundational
Demilitarized Zone (DMZ)A network segment between an organization's internal network and the Internet that hosts public-facing services.Foundational
Denial of Authorization to Operate (DATO)AO decision that the risk of operating a system is unacceptable, so it must not operate or must cease operating.Advanced
Denial of Service (DoS)An attack that makes a system or network unavailable to legitimate users by exhausting resources or crashing services.Foundational
DenormalizationIntentionally adding redundancy, for example by merging tables or duplicating columns, to speed reads and simplify queries.Intermediate
Denylist ValidationInput validation that rejects values matching known-bad patterns and accepts everything else.Foundational
DependabotA GitHub feature that alerts on vulnerable dependencies and automatically opens pull requests to update them.Foundational
Dependency ConfusionA supply chain risk in which a package manager installs a malicious public package instead of an internal private package with the same name.Intermediate
Dependency Lock FileTerraform's .terraform.lock.hcl file recording exact provider versions and checksums selected during init.Intermediate
Dependency ManagementDeclaring, resolving, pinning, and updating the external libraries an application relies on.Foundational
Dependency PinningSpecifying exact versions (and ideally cryptographic hashes) of dependencies so builds use known, reviewed components.Intermediate
Dependency TypesClassification of activity dependencies as mandatory, discretionary, external, or internal.Intermediate
Dependency ViewGraphical map of a CI and its upstream and downstream relationships.Foundational
Dependent PicklistPicklist whose available values are filtered by the value chosen in a controlling picklist or checkbox field.Foundational
DeploymentA Kubernetes workload object that manages ReplicaSets to provide declarative updates, scaling, and rollback for stateless pods.Foundational
Deployment ConnectionSetting that authorizes one org to send change sets to another related org.Intermediate
Deployment FrequencyA DORA metric measuring how often an organization successfully deploys code to production.Foundational
Deployment Image Servicing and Management (DISM)A Windows command-line tool for servicing Windows images and repairing the component store.Intermediate
Deployment PipelinesA Power BI and Fabric feature for promoting content through development, test and production workspaces, with deployment rules for data sources and parameters.Advanced
Deployment RingA group of devices that receives updates or changes in stages, from pilot to broad deployment.Intermediate
Deployment SlotLive App Service environment with its own hostname used to stage a new version and swap it into production with no downtime.Intermediate
DeprovisioningRemoving or disabling a user's accounts and access when they leave or no longer need it.Foundational
Derived TableA subquery in the FROM clause that acts as a temporary inline table, which must have an alias.Intermediate
Descriptive AnalyticsAnalytics that answers 'what happened?' by summarizing historical data through reports, dashboards and KPIs.Foundational
Descriptive StatisticsStatistics that summarize and describe the features of a dataset, such as its center, spread and shape, without generalizing beyond it.Foundational
Design CenterWeb-based Anypoint tool for designing API specifications and fragments.Foundational
Design for X (DfX)Technical guidelines applied during design to optimize a specific aspect such as reliability, cost, assembly, or usability.Advanced
Design of Experiments (DOE)Statistical method for determining which factors and interactions affect a process output.Advanced
Design ThinkingHuman-centered approach to innovation: empathize, define, ideate, prototype, and test.Foundational
Designated Forwarder (DF)The single EVPN PE on a multihomed Ethernet segment responsible for forwarding BUM traffic toward the segment for a given VLAN.Advanced
Designated Intermediate System (DIS)The IS-IS router elected on a broadcast segment to create the pseudonode and send periodic CSNPs.Advanced
Designated Port (DP)The port on each segment that offers the lowest cost path to the root and forwards toward that segment.Foundational
Designated Router (DR)The OSPF router elected on a multi-access segment to form full adjacencies with all others and originate the Type 2 LSA.Intermediate
Desired State Configuration (DSC)A PowerShell declarative configuration management platform that defines and enforces how servers should be configured.Advanced
Desktop as a Service (DaaS)Cloud-hosted virtual desktops delivered to users over the network, managed by a provider on a subscription basis.Foundational
Destination UnreachableICMP type 3 message indicating a packet could not be delivered, with codes giving the reason.Intermediate
Detection and AnalysisThe incident response phase focused on identifying potential incidents, validating them and determining scope and impact.Foundational
Detection EngineeringThe discipline of designing, building, testing and maintaining threat detections as code.Advanced
Detection RiskRisk that the auditor's procedures fail to detect a material error or misstatement.Intermediate
Detective ControlControl that identifies and records an undesired event after or while it occurs.Foundational
Detective GuardrailGovernance control that identifies noncompliant resources after creation and reports or remediates them.Intermediate
Determine BudgetProcess of aggregating estimated costs of activities or work packages to establish an authorized cost baseline.Intermediate
Deterrent ControlControl that discourages potential attackers or violators from attempting an action.Foundational
DetonationExecuting a suspicious file or opening a URL in a sandbox to trigger and observe any malicious behavior.Intermediate
Dev ContainerA container-based development environment defined by devcontainer.json, used by VS Code, Codespaces, and other tools.Intermediate
Dev HubOrg feature that allows creating and managing scratch orgs and second-generation packages.Intermediate
Develop Project CharterProcess of creating the document that formally authorizes the project's existence.Foundational
Develop ScheduleProcess of analyzing activity sequences, durations, resources, and constraints to create the schedule model.Intermediate
Develop TeamProcess of improving competencies, team interaction, and the team environment to enhance performance.Intermediate
Developer ConsoleBrowser-based IDE in Salesforce for editing code, running tests and SOQL, and viewing debug logs.Foundational
Developer ModeA mobile or OS setting that unlocks advanced options such as USB debugging.Intermediate
Developer Pro SandboxMetadata-only sandbox with 1 GB data storage and a one-day refresh interval, for larger dev and test datasets.Foundational
Developer SandboxSandbox type that copies production metadata only, with 200 MB data storage and a one-day refresh interval.Foundational
DevelopersThe Scrum accountability for people committed to creating any aspect of a usable Increment each Sprint.Foundational
Development Value StreamIn SAFe, the sequence of activities to convert a business hypothesis into a technology-enabled solution.Advanced
Device ManagerA Windows console (devmgmt.msc) for viewing hardware and managing device drivers.Foundational
Device Mapper Multipath (DM-Multipath)A Linux feature that combines multiple I/O paths to a SAN LUN into one device for redundancy and load balancing.Advanced
Device MobilityA CUCM feature that applies site-specific settings to phones based on the IP subnet they connect from when roaming between sites.Advanced
Device PoolA CUCM template of common settings such as CM Group, region, date/time group, location and SRST reference assigned to devices.Foundational
Device Posture CheckEvaluating a device's security state, such as patch level, encryption, and EDR status, before granting access.Intermediate
DevOpsA culture and set of practices that unify software development and IT operations to deliver changes quickly, safely, and reliably.Foundational
DevSecOpsThe integration of security practices and automated security testing into every stage of the DevOps pipeline.Intermediate
dfThe Linux disk free command that reports total, used and available space for each mounted filesystem.Foundational
DFARS 252.204-7012Defense acquisition clause requiring contractors to safeguard covered defense information and report cyber incidents.Intermediate
DFS Namespaces (DFS-N)A Windows Server feature that presents shared folders from multiple servers under one logical UNC path.Intermediate
DFS Replication (DFSR)A Windows Server multi-master replication engine that synchronizes folders between servers using Remote Differential Compression.Intermediate
DHCP Exclusion RangeAddresses within a scope that the DHCP server will not assign, reserved for statically configured devices.Foundational
DHCP FailoverA Windows Server DHCP feature where two servers share lease information for a scope in load-balance or hot-standby mode.Intermediate
DHCP LeaseThe period during which a client may use an address assigned by DHCP.Foundational
DHCP Option 150A Cisco-specific DHCP option that gives IP phones a list of TFTP server addresses for downloading configuration files.Foundational
DHCP Option 43A vendor-specific DHCP option used to give APs the IP address of their wireless controller.Intermediate
DHCP OptionsAdditional configuration parameters a DHCP server sends to clients, identified by number.Intermediate
DHCP Relay AgentA router or Layer 3 switch function that forwards DHCP broadcasts from clients to a DHCP server on another subnet as unicast.Intermediate
DHCP ReservationA DHCP configuration that always assigns the same IP address to a specific client, identified by its MAC address or client ID.Foundational
DHCP ScopeThe range of IP addresses and associated settings a DHCP server can assign on a particular subnet.Foundational
DHCPv6The IPv6 version of DHCP, which can assign addresses (stateful) or just options such as DNS servers (stateless).Intermediate
Diagnostic AnalyticsAnalytics that answers 'why did it happen?' through drill-down, correlation, segmentation and root-cause analysis.Foundational
Dial PeerAn IOS configuration entry that defines a call leg's matching criteria and destination, either POTS (telephony port) or VoIP (IP target).Foundational
Dial-Peer Group (DPG)A CUBE feature that lets an inbound dial peer explicitly select a list of outbound dial peers, bypassing destination-pattern matching.Advanced
Dialed Number Analyzer (DNA)A CUCM serviceability tool that simulates digit analysis to show how a dialed number would be routed for a given CSS.Intermediate
DiameterAAA protocol designed as a successor to RADIUS, using TCP or SCTP on port 3868.Intermediate
Diamond Model of Intrusion AnalysisAn analytic model describing every intrusion event by four core features: adversary, capability, infrastructure and victim.Intermediate
DictionarySystem table (sys_dictionary) holding definitions of every table and field, including type, length, defaults and attributes.Intermediate
Dictionary AttackA password attack that tries words from a list of common passwords and dictionary terms.Foundational
Dictionary OverrideSetting that lets a child table use a different default, reference qualifier, mandatory or read-only value for an inherited field.Advanced
Differential BackupA backup that copies all data changed since the last full backup, growing each day until the next full.Foundational
Differential PrivacyA mathematical privacy guarantee that limits how much any individual's data can affect a model's or query's output.Advanced
Differentiated Services (DiffServ)A scalable QoS model that classifies and marks packets with DSCP values and applies per-hop behaviors at each router.Foundational
Differentiated Services Code Point (DSCP)A 6-bit value in the IP header used to mark packets for quality-of-service treatment.Intermediate
Differentiated Services Code Point MappingTranslating Layer 3 DSCP markings to 802.11 user priorities and back, for end-to-end wireless QoS.Advanced
Diffie-Hellman (DH)Key agreement protocol that lets two parties derive a shared secret over an insecure channel.Foundational
DiffractionBending of an RF wave around the edge of an obstacle, creating an RF shadow behind it.Intermediate
Diffusing Update Algorithm (DUAL)The EIGRP algorithm that guarantees loop-free paths and selects successors and feasible successors.Intermediate
Diffusion ModelA generative model that learns to create data by reversing a gradual noising process.Intermediate
Digit Discard Instructions (DDI)CUCM settings that remove parts of a dialed number, such as PreDot to strip an access code, before sending it to the destination.Intermediate
Digital CertificateElectronic document signed by a CA that binds a public key to an identity such as a domain, person, or device.Foundational
Digital ForensicsThe scientific collection, preservation, analysis and presentation of digital evidence in a legally defensible manner.Foundational
Digital Operational Resilience Act (DORA)EU Regulation (2022/2554), applicable from 17 January 2025, on ICT risk management for financial entities.Advanced
Digital Signal 0 (DS0)A single 64 kbps digital voice channel, the basic building block of T1, E1 and ISDN circuits.Foundational
Digital Signal Processor (DSP)A specialized processor on voice gateways and routers that performs codec conversion, conferencing, transcoding and echo cancellation.Intermediate
Digital SignatureCryptographic value created with a private key over a message hash that proves origin, integrity, and non-repudiation.Foundational
Digital Signature Algorithm (DSA)Legacy NIST signature algorithm based on the discrete logarithm problem.Intermediate
Digital Subscriber Line (DSL)Broadband Internet over telephone copper pairs, using frequencies above voice so phone service can share the line.Foundational
Digital Visual Interface (DVI)A legacy video interface that can carry digital (DVI-D), analog (DVI-A), or both (DVI-I) signals.Foundational
DigitizerThe touch-sensing layer of a screen or tablet that converts touch or pen input into coordinates.Foundational
Dimension TableA table of descriptive attributes (who, what, where, when) used to filter, group and label facts.Foundational
Dimensional ModelingA data modeling technique that organizes analytic data into facts (measurable events) and dimensions (descriptive context).Intermediate
Dimensionality ReductionTechniques that reduce the number of input features while preserving as much useful information as possible.Intermediate
Dimensions and Measures (Tableau)Tableau's field roles: dimensions are qualitative values that slice the view; measures are quantitative values that are aggregated.Foundational
Dipole AntennaThe simplest common omnidirectional antenna, typically 2.14 dBi gain.Foundational
dir CommandA Windows command that lists files and folders in a directory.Foundational
Direct and Indirect CostsDirect costs are attributable directly to the project; indirect costs are shared overhead allocated across projects.Foundational
Direct and Manage Project WorkProcess of leading and performing the work defined in the plan and implementing approved changes.Intermediate
Direct Attach Copper (DAC)A fixed-length twinax cable with transceiver connectors (such as SFP+ or QSFP28) permanently attached on both ends.Intermediate
Direct Guest JoinA capability that lets a meeting room device join another platform's meeting as a guest without full interop gateways.Intermediate
Direct Input Box (DI box)A device that converts unbalanced high-impedance signals to balanced low-impedance mic-level signals for long runs.Intermediate
Direct Internet Access (DIA)Sending branch Internet traffic directly out a local Internet link instead of backhauling it to a data center.Intermediate
Direct Inward Dialing (DID)A carrier service that routes external calls directly to individual internal extensions without an operator.Foundational
Direct LakeA Fabric storage mode in which semantic models load Delta Parquet column data directly from OneLake into memory on demand, without import refresh.Advanced
Direct Preference Optimization (DPO)A preference-tuning method that optimizes a model directly on preferred vs. rejected responses without a separate reward model.Advanced
Direct RoutingA Teams Phone PSTN option in which a customer-managed certified SBC connects Teams to a carrier or existing telephony.Intermediate
Direct-Attached Storage (DAS)Storage connected directly to a single server, such as internal drives or an external SAS enclosure, without a network.Foundational
Direct-Sequence Spread Spectrum (DSSS)Spreading each bit across a wide channel using a chipping code, used by 802.11 and 802.11b.Intermediate
Direct-to-Chip Liquid CoolingCooling that circulates liquid through cold plates mounted on CPUs and GPUs to remove heat at the source.Advanced
Direct-View LED Display (dvLED)A display built from tiled modules of red, green and blue LEDs that emit light directly, with no LCD or backlight.Intermediate
Directed Acyclic Graph (DAG)A graph of tasks with directed dependencies and no cycles, used to define pipeline workflows and execution plans.Intermediate
Directed BroadcastA packet sent to the broadcast address of a specific remote subnet, which a router could forward to that subnet.Intermediate
Directive ControlControl that specifies required behavior, such as policies, standards, and procedures.Foundational
Directory HandlerA Unity Connection object that lets callers find a user by spelling or speaking a name and then transfers them.Intermediate
Directory ListingA web server setting that displays a list of files in a directory when no index file is present.Foundational
Directory Number (DN)A line number configured on a CUCM device or device profile, associated with a partition and line-level settings.Foundational
Directory ServiceCentralized database that stores and organizes information about users, groups, devices, and resources for authentication and lookup.Foundational
Directory Services Restore Mode (DSRM)A special boot mode for domain controllers that takes AD DS offline for maintenance or restoration, using a local DSRM password.Advanced
Directory TraversalAn attack that manipulates file paths with sequences like ../ to access files outside the intended directory.Foundational
Directory URIA SIP URI such as user@example.com assigned to a CUCM user or DN so callers can dial by alphanumeric address.Intermediate
DirectQueryA Power BI storage mode that sends queries to the source at report time instead of importing data, keeping results current.Intermediate
DirectX Diagnostic Tool (dxdiag)A Windows tool that reports display, sound, and input device information and DirectX status.Foundational
Dirty ReadReading data written by another transaction that has not yet committed and may be rolled back.Intermediate
Disassociation FrameA management notification frame that ends an association but not authentication.Intermediate
Disaster Recovery (DR)Policies, tools and procedures for restoring IT systems and data after a disruptive event such as a regional outage or ransomware.Foundational
Disaster Recovery as a Service (DRaaS)Cloud service that replicates servers and data to a provider and orchestrates failover so workloads can recover after a disaster.Intermediate
Disaster Recovery Plan (DRP)A documented plan for restoring IT systems, data and infrastructure after a disruptive event.Foundational
Discard RouteA route that silently drops matching packets, used to anchor aggregates and prevent loops (Junos discard next hop).Intermediate
Disciplined Agile (DA)PMI's hybrid, tool-kit approach that helps teams choose their way of working (WoW) based on context.Advanced
DiscoveryServiceNow ITOM application that finds devices and applications on the network and populates the CMDB.Foundational
Discovery CredentialsStored credentials (SSH, Windows, SNMP, VMware, cloud) used by MID Servers to access discovered devices.Intermediate
Discovery PatternStep-based identification and exploration logic in Pattern Designer used by Discovery and Service Mapping.Advanced
Discovery SamplingAttribute sampling used to find at least one instance of a critical error, such as fraud, if it exists above a given rate.Advanced
Discovery ScheduleConfiguration defining what IP ranges, behaviors and MID Servers Discovery uses and when it runs.Intermediate
Discrete and Continuous FieldsTableau field types: discrete (blue pills) create headers and distinct values; continuous (green pills) create axes.Foundational
Discrete DataQuantitative data that take countable values, usually integers, such as number of orders or defects.Foundational
Discrete EffortWork that can be planned and measured and that yields a specific output.Advanced
Discretionary Access Control (DAC)Access control model where the owner of a resource decides who may access it.Foundational
Discriminative ModelA model that learns the boundary between classes, estimating P(label | input).Intermediate
DisinformationDeliberately false or misleading information spread to deceive, often as part of an influence campaign.Foundational
Disk Cleanup (cleanmgr)A Windows utility that frees space by removing temporary files, update leftovers, and other unneeded data.Foundational
Disk ManagementA Windows console (diskmgmt.msc) for initializing disks and creating, formatting, and resizing partitions.Foundational
Disk UtilityThe macOS tool for managing disks, volumes, formatting, and running First Aid repairs.Foundational
diskpartA Windows command-line utility for managing disks, partitions, and volumes.Intermediate
Dispatcher WorkspaceFSM workspace for dispatchers to view, schedule and assign work order tasks on maps and calendars.Intermediate
Display Image Size for 2D Content in Audiovisual Systems (DISCAS)The ANSI/AVIXA V202.01 standard for calculating display image size based on viewing distance and content type.Advanced
Display ResolutionThe number of pixels a display shows horizontally and vertically, such as 1920 x 1080.Foundational
DisplayPort (DP)A digital display interface common on PCs and monitors that supports high refresh rates and daisy-chaining.Foundational
DisplayPort Alternate Mode (DP Alt Mode)A USB-C feature that carries native DisplayPort video over the USB-C connector.Intermediate
Distance-Vector Routing ProtocolA routing protocol class where routers share their routing tables with neighbors and know only distance and direction to destinations.Foundational
DISTINCT KeywordA SELECT modifier that removes duplicate rows from the result.Foundational
Distinguished Encoding Rules (DER)Binary encoding format for X.509 certificates and keys.Intermediate
Distinguished Name (DN)The full LDAP path that uniquely identifies an object in a directory, built from components such as CN, OU and DC.Intermediate
Distribute ListA Cisco command that filters routing updates in or out of a routing protocol using an ACL, prefix list or route map.Intermediate
Distributed Anycast GatewayA fabric design where every leaf hosts the same default gateway IP and MAC for a subnet, so hosts route at their local leaf.Advanced
Distributed Control System (DCS)A process control system in which controllers are distributed throughout a single plant or facility under centralized supervision.Intermediate
Distributed Coordination Function (DCF)The mandatory 802.11 contention-based access method implementing CSMA/CA without QoS.Advanced
Distributed Denial of Service (DDoS)A denial-of-service attack launched from many sources, often a botnet, to overwhelm a target.Foundational
Distributed Interframe Space (DIFS)The interframe space non-QoS stations wait before contending: SIFS plus two slot times.Advanced
Distributed TracingTracking a single request as it flows across multiple services by propagating a trace context and recording timed spans.Intermediate
Distributed TransactionA transaction that spans multiple databases or nodes and must still be atomic across all of them.Advanced
Distribution LayerThe aggregation layer of a hierarchical network that connects access switches and enforces policy, routing and summarization.Intermediate
Distribution System (DS)The system that interconnects APs and integrates the WLAN with other networks.Intermediate
Distribution System Medium (DSM)The physical medium connecting APs in a distribution system, usually 802.3 Ethernet.Advanced
Distroless ImageA minimal container image containing only the application and its runtime dependencies, without a shell or package manager.Advanced
Diverging Color PaletteA two-hue color scale with a neutral midpoint, used for data that deviates above and below a meaningful center such as zero or a target.Intermediate
DLL InjectionForcing a running process to load a malicious dynamic-link library.Advanced
DLL Side-LoadingPlacing a malicious DLL alongside a legitimate signed application so the application loads it.Advanced
DMADVSix Sigma design methodology: Define, Measure, Analyze, Design, Verify.Intermediate
DMAICSix Sigma improvement cycle: Define, Measure, Analyze, Improve, Control.Foundational
dmesgA Linux command that prints the kernel ring buffer containing hardware detection, driver and kernel messages.Foundational
DMVPN Phase 3The DMVPN mode where the hub sends NHRP redirects and spokes install NHRP shortcut routes, allowing hub summarization.Advanced
DNFThe default high-level package manager on RHEL, Fedora and derivatives, successor to YUM, resolving dependencies from repositories.Foundational
DNP3Distributed Network Protocol 3, an industrial protocol used mainly in electric and water utilities for communication between SCADA masters, RTUs and IEDs.Intermediate
DNP3 Secure Authentication (DNP3-SA)An extension to DNP3 that authenticates critical messages using HMAC-based challenge-response and session keys.Advanced
DNS AmplificationA reflected DDoS attack that abuses open DNS resolvers to send large responses to a spoofed victim address.Intermediate
DNS CacheTemporary storage of DNS answers on clients and resolvers for the duration of each record's TTL.Foundational
DNS Cache PoisoningInserting false records into a DNS resolver's cache so users are directed to malicious IP addresses.Intermediate
DNS EnumerationDiscovering hostnames, records and infrastructure details by querying a target's DNS.Foundational
DNS over HTTPS (DoH)Encrypting DNS queries inside HTTPS on TCP 443 to provide privacy from on-path observers.Intermediate
DNS over TLS (DoT)Encrypting DNS queries with TLS on dedicated TCP port 853.Intermediate
DNS RebindingA technique in which a domain's DNS answer changes between validation and use, so a host check passes but the request goes to an internal IP.Advanced
DNS SinkholeA DNS server configuration that returns a controlled IP for known malicious domains to block and identify infected hosts.Intermediate
DNS TunnelingEncoding data or command-and-control traffic inside DNS queries and responses to bypass network controls.Advanced
DNS ZoneA portion of the DNS namespace managed as a unit, with its records stored in a zone file or directory.Intermediate
DNS Zone Transfer (AXFR)A DNS mechanism for replicating zones between servers that, if allowed to anyone, leaks every record in a domain.Intermediate
DNS64A DNS function that synthesizes AAAA records from A records for IPv6-only clients, pointing them at a NAT64 prefix.Advanced
DockerA platform and toolset for building, shipping, and running containers, including Docker Engine, the docker CLI, Docker Compose, and Docker Desktop.Foundational
Docker ComposeA tool for defining and running multi-container applications using a compose.yaml file.Foundational
Docker EngineThe client-server application consisting of the dockerd daemon, a REST API, and the docker CLI that builds and runs containers.Intermediate
Docker HubDocker's public cloud registry hosting official images, verified publisher images, and user repositories.Foundational
Docker LayerA read-only filesystem diff produced by a Dockerfile instruction; images are stacks of layers combined by a union filesystem.Intermediate
Docker Network DriverThe networking mode for Docker containers: bridge, host, overlay, macvlan, ipvlan, or none.Intermediate
Docker SwarmDocker's built-in container orchestration mode that clusters Docker hosts into managers and workers running replicated services.Intermediate
Docker VolumeDocker-managed persistent storage that exists independently of a container's lifecycle.Foundational
DockerfileA text file of instructions (FROM, RUN, COPY, CMD, and others) that Docker uses to build a container image.Foundational
Docking StationA device that connects a laptop to monitors, network, power, and peripherals through one connection.Foundational
Document AnalysisElicitation technique of reviewing existing documentation to understand context and requirements.Foundational
Document DatabaseA NoSQL database that stores self-describing documents (JSON or BSON) whose structure can vary from document to document.Foundational
Document EmbeddingStoring related data inside a parent document (embedding) rather than in a separate collection with references.Intermediate
Documentation Address RangeIP ranges reserved for examples in documentation and training: 192.0.2.0/24, 198.51.100.0/24 and 203.0.113.0/24 (TEST-NET-1 to 3).Intermediate
DoD 8570.01-MFormer DoD manual that required certifications for information assurance workforce categories, superseded by DoD 8140.Intermediate
DoD Cloud Computing Security Requirements Guide (CC SRG)DoD guide defining security requirements and impact levels (IL2, IL4, IL5, IL6) for cloud services.Advanced
DoD Cyber Workforce Framework (DCWF)DoD taxonomy of cyberspace work roles with associated tasks, knowledge, and skills used for 8140 qualification.Intermediate
DoD Directive 8140.01DoD policy establishing management of the cyberspace workforce across IT, cybersecurity, cyber effects, intelligence, and enabler roles.Intermediate
DoD Manual 8140.03DoD manual defining the Cyberspace Workforce Qualification and Management Program.Intermediate
DOM-Based Cross-Site ScriptingXSS that occurs entirely in client-side JavaScript when it writes untrusted data from a source into a dangerous sink.Intermediate
Domain Controller (DC)A Windows Server running AD DS that authenticates users and computers and holds a writable or read-only copy of the directory.Foundational
Domain Generation Algorithm (DGA)An algorithm in malware that generates many pseudo-random domain names to locate its command-and-control servers.Advanced
Domain HijackingTaking unauthorized control of a domain registration, often by compromising the registrar account.Intermediate
Domain Information Groper (dig)A Linux/macOS DNS query tool that shows detailed responses, including flags, TTLs and authority sections.Intermediate
Domain IntegrityThe rule that every column value comes from the column's valid set of values, enforced by data types, CHECK, NOT NULL and DEFAULT.Intermediate
Domain JoinAdding a computer to an Active Directory domain so it trusts the domain for authentication and receives Group Policy.Foundational
Domain Name System (DNS)The hierarchical, distributed system that translates domain names into IP addresses and other records, using UDP and TCP port 53.Foundational
Domain Name System Security Extensions (DNSSEC)DNS extensions that digitally sign records so resolvers can verify their authenticity and integrity.Intermediate
Domain Name System Service Record (DNS SRV)A DNS record type that maps a service and protocol to the hostname, port, priority and weight of servers that provide it.Intermediate
Domain Naming MasterThe forest-wide FSMO role that controls adding and removing domains and application partitions in the forest.Intermediate
Domain TreeOne or more AD domains sharing a contiguous DNS namespace and connected by two-way transitive parent-child trusts.Intermediate
Domain Validation Certificate (DV)Certificate issued after the CA verifies only that the requester controls the domain.Foundational
DORA MetricsFour key software delivery metrics from the DevOps Research and Assessment program: deployment frequency, lead time, change failure rate, and recovery time.Intermediate
DORA ProcessThe four-message DHCP exchange: Discover, Offer, Request, Acknowledge.Foundational
Dot ProductThe sum of element-wise products of two vectors, used as a similarity score in retrieval and attention.Intermediate
Dot-WalkingNavigating through reference fields to access fields on related records in lists, filters, reports and scripts.Foundational
Dotted-Decimal NotationThe format for writing IPv4 addresses as four decimal numbers (0-255) separated by periods.Foundational
Double Data Rate SDRAM (DDR SDRAM)Synchronous DRAM that transfers data on both the rising and falling edges of the clock signal.Foundational
Double DiamondDesign process model with four phases: Discover, Define, Develop, Deliver.Intermediate
Double ExtortionA ransomware tactic that both encrypts data and threatens to leak stolen copies unless a ransom is paid.Intermediate
Double FreeCalling free on the same memory twice, which can corrupt the heap allocator and enable code execution.Advanced
Double-Submit CookieA stateless CSRF defense in which a random value is sent both in a cookie and in a request parameter or header, and the server checks they match.Advanced
Downgrade AttackForcing a system to use an older, weaker protocol or cipher version that the attacker can exploit.Intermediate
DowntiltAngling an antenna's beam downward to aim coverage at the ground area that needs it.Advanced
dpkgThe low-level Debian package tool that installs, removes and queries .deb files without repository dependency resolution.Foundational
DREADA threat risk-rating model scoring Damage, Reproducibility, Exploitability, Affected users and Discoverability.Intermediate
Drill-DownNavigating from summarized data to a more detailed level along a hierarchy, such as Year to Quarter to Month.Foundational
Drill-ThroughNavigating from a summary value to a separate detail page or report, filtered to the selected context.Intermediate
Drive EnduranceThe rated amount of data an SSD can write over its life, given as TBW or DWPD.Intermediate
Drive Form FactorThe physical size standard for storage devices, such as 3.5-inch, 2.5-inch, M.2, and U.2.Foundational
Drive-by DownloadAn unintended download of malicious code that occurs simply by visiting a compromised or malicious website.Foundational
Driver RollbackRestoring the previously installed version of a device driver.Foundational
DROP StatementThe DDL command that permanently removes a database object, such as a table, view, index or schema, together with its data.Foundational
DropoutA regularization technique that randomly deactivates a fraction of neurons during each training step.Intermediate
DropperMalware whose purpose is to install another malicious payload that it carries within itself.Intermediate
DTU Purchasing ModelAn Azure SQL Database pricing model that bundles CPU, memory and I/O into Database Transaction Units across Basic, Standard and Premium tiers.Intermediate
duThe Linux disk usage command that totals space consumed by files and directories.Foundational
Dual Axis ChartA chart that overlays two measures with independent axes on the same pane, often with different mark types.Intermediate
Dual BootInstalling two operating systems on one computer and choosing which to start at boot.Intermediate
Dual ControlRequiring two or more authorized people to act together to perform a sensitive operation.Intermediate
Dual In-Line Memory Module (DIMM)The standard desktop memory module with separate contacts on each side of the board.Foundational
Dual StackRunning IPv4 and IPv6 simultaneously on the same devices and network.Foundational
Dual Storage ModeA Power BI table storage mode that can act as Import or DirectQuery depending on the query, which avoids weak relationships in composite models.Advanced
Dual-Band Access PointAn AP with radios operating simultaneously in two bands, typically 2.4 GHz and 5 GHz.Foundational
Dual-Channel MemoryA memory configuration that uses two channels simultaneously to increase bandwidth.Foundational
Dual-Tone Multi-Frequency (DTMF)Touch-tone signaling in which each keypad digit is a pair of simultaneous tones, one low-group and one high-group frequency.Foundational
Dual-Track AgileRunning product discovery and delivery in parallel tracks within the same team.Advanced
Due CareActing as a reasonable person would to protect assets, by implementing and maintaining appropriate safeguards.Foundational
Due DiligenceInvestigation and analysis performed to understand risks before and while making decisions.Foundational
Due Professional CareApplying the care and skill expected of a reasonably prudent and competent auditor.Intermediate
Dumpster DivingSearching trash for discarded information or media that can aid an attack.Foundational
Duplex MismatchA misconfiguration where one end of a link runs full duplex and the other half duplex, causing poor performance.Foundational
Duplexing AssemblyThe printer component that flips paper to enable automatic double-sided printing.Foundational
Duplicate Address Detection (DAD)An IPv6 process that checks whether an address is already in use on the link before assigning it.Intermediate
Duplicate Record DetectionIdentifying records that represent the same entity, through exact key matches or fuzzy matching of attributes.Intermediate
Duplicate RuleRule that uses a matching rule to alert or block users when they create or edit a record that looks like a duplicate.Foundational
DurabilityThe ACID property that committed changes persist even after a crash or power loss.Foundational
Durable FunctionsAzure Functions extension for writing stateful, long-running orchestrations in code.Advanced
Duration FieldThe MAC header field indicating how long, in microseconds, the medium will remain reserved.Advanced
Duty CycleThe percentage of time an RF transmitter is active on a frequency.Intermediate
Dwell TimeThe length of time an attacker remains undetected in an environment from initial compromise to detection.Intermediate
Dynamic ActionsFeature that lets admins configure which actions appear on a Lightning record page and under what conditions.Intermediate
Dynamic Application Security Testing (DAST)Testing a running application from the outside by sending crafted requests to find vulnerabilities.Intermediate
Dynamic Bandwidth Selection (DBS)Cisco RRM feature that automatically selects channel width per AP.Advanced
Dynamic Channel Assignment (DCA)Cisco RRM algorithm that automatically assigns AP channels to minimize interference.Advanced
Dynamic DashboardDashboard that displays data according to the logged-in viewer's access rather than a fixed running user.Intermediate
Dynamic Data Masking (DDM)Masking sensitive column values in query results for unauthorized users at run time without changing the stored data.Intermediate
Dynamic Emergency CallingEmergency calling that determines a user's current location from the network so emergency services receive accurate location.Advanced
Dynamic FormsLightning feature that places individual fields and field sections directly on a Lightning page with their own visibility rules.Intermediate
Dynamic Frequency Selection (DFS)A requirement that 5 GHz devices detect radar and vacate the channel when radar is present.Intermediate
Dynamic Host Configuration Protocol (DHCP)A protocol that automatically assigns IP addresses and other configuration to hosts, using UDP ports 67 (server) and 68 (client).Foundational
Dynamic IP AddressAn IP address automatically assigned to a device, usually by DHCP, for a limited lease period.Foundational
Dynamic Malware AnalysisExecuting malware in a controlled environment to observe its behavior, network activity and system changes.Intermediate
Dynamic MemoryA Hyper-V feature that adjusts a VM's memory between minimum and maximum values based on demand.Intermediate
Dynamic MicrophoneA rugged microphone that generates signal by moving a coil within a magnetic field, needing no external power.Foundational
Dynamic Multipoint VPN (DMVPN)A Cisco hub-and-spoke VPN design using mGRE, NHRP and usually IPsec that can build dynamic spoke-to-spoke tunnels.Advanced
Dynamic NATNAT that maps inside addresses to public addresses drawn from a pool on a first-come, first-served, one-to-one basis.Foundational
Dynamic RAM (DRAM)Memory that stores each bit in a capacitor and must be refreshed constantly; used for system RAM.Intermediate
Dynamic RangeThe ratio in decibels between the loudest undistorted level and the noise floor of a system or signal.Intermediate
Dynamic Rate Switching (DRS)Automatic adjustment of a client's data rate as signal quality changes; also called rate shifting.Intermediate
Dynamic Routing Gateway (DRG)OCI virtual router that connects VCNs to on-premises networks, other VCNs and other regions.Intermediate
Dynamic Row-Level SecurityRLS that filters data using the signed-in user's identity, typically through USERPRINCIPALNAME() and a user-to-entitlement mapping table.Advanced
Dynamic SecretsCredentials generated on demand for each client with a short lease, then automatically revoked.Advanced
Dynamic SOQLSOQL built as a string at runtime and executed with Database.query or Database.queryWithBinds.Advanced
Dynamic SQLSQL statements built as strings at run time and then executed, for example with EXEC, sp_executesql or EXECUTE IMMEDIATE.Advanced
Dynamic Systems Development Method (DSDM)Agile project framework emphasizing fixed time and cost with prioritized, flexible features.Advanced
Dynamic TableA Snowflake table defined by a query that Snowflake keeps refreshed automatically to meet a declared target lag.Advanced
Dynamic Trunking Protocol (DTP)A Cisco protocol that negotiates whether a link becomes a trunk, using modes dynamic auto, dynamic desirable, trunk and access.Intermediate
Dynamic VLAN AssignmentAssigning a client VLAN based on RADIUS attributes returned after authentication.Intermediate
Dynamics ProcessingProcessing that changes a signal's level based on its amplitude, including compressors, limiters, expanders and gates.Intermediate
DynamoDB Accelerator (DAX)Fully managed in-memory cache for DynamoDB that delivers microsecond read latency with API compatibility.Intermediate
DynamoDB Capacity ModesDynamoDB billing options: on-demand (pay per request) or provisioned (set read and write capacity units, optionally auto scaled).Advanced
DynamoDB Global TablesDynamoDB feature that replicates tables across multiple AWS regions as a multi-active (multi-writer) database.Advanced
DynamoDB StreamsTime-ordered log of item-level changes in a DynamoDB table, retained for 24 hours and consumable by Lambda.Advanced

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