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Terminology

2205 terms, tools, patterns and metrics an architect is expected to use precisely. Each one gets a short explanation of what it is, and — where it matters — what it is commonly confused with. Search filters as you type; the column headers sort.

All areas2205 Architecture Fundamentals77 Distributed Systems107 Data Architecture110 Cloud Architecture94 Networking88 API & Integration Architecture82 Reliability & Resilience75 Observability70 Performance & Capacity Engineering72 Security Architecture86 Cost Architecture & FinOps71 Business Architecture67 Architecture Communication67 Enterprise Architecture66 Legacy Modernization71 AI-Era Architecture69 Software Architecture & Engineering71 Architecture Patterns71 Architecture Decision-Making63 The Architect's Meta-Skills61 Delivery & Release Engineering66 Platform Engineering & Developer Experience70 Testing & Quality Architecture66 Data Platform Architecture64 Streaming & Real-Time Data69 Data Governance & Semantics69 Frontend & Experience Architecture66 Edge, Mobile & IoT68 Regulatory & Data Protection Architecture65 Assurance, Audit & Model Risk64
Kind Any concept794 practice734 pattern368 metric125 case-study77 tool62 protocol45

2205 terms shown.

Term Kind Topic What it is
Deployment Topology View concept Deployment Diagrams A diagram showing where software actually runs — regions, zones, networks and hosts — which is where availability and cost properties become visible.
Deprecation Brownout Sunset Rehearsal, Scheduled Dark Window practice Backward Compatibility An announced, time-boxed window in which a deprecated interface returns its retirement error, used to convert an abstract sunset date into a failure the consumer sees in their own monitoring.
Deprecation Window practice Platform API Deprecation The stated period between announcing that an internal interface will be removed and removing it, with the removal actually happening at the end.
Derived Store Discipline One Authoritative Store Per Fact, No Dual Authority concept Polyglot Persistence The rule that every fact has exactly one authoritative store and every other copy is explicitly derived, rebuildable and populated by a documented pipeline - the discipline that makes multiple datastores defensible.
Design Authority practice Design Authority The body or role that approves significant designs — valuable when it improves decisions, harmful when it becomes a queue.
Design Patterns concept Design Patterns Named solutions to recurring design problems — valuable primarily as shared vocabulary, and harmful when applied as a goal.
Design Review Trigger practice Security Design Review The stated conditions under which a change requires security review, so that review capacity goes to what warrants it and everything else proceeds.
Design System concept Design Systems A versioned library of components, tokens and patterns that encodes an organisation's interface decisions as reusable code.
Destination Isolation Per-Destination Queues, Independent Fan-Out pattern Event-Driven Integration Fanning events out by writing to a queue per destination rather than delivering synchronously to many, so that one failing or slow destination cannot delay, block or duplicate delivery to the others.
Deterministic Tokenisation practice Tokenisation & Masking Replacing a sensitive value with a stable surrogate so the same input always yields the same token, preserving joins while removing the value.
Developer Environment on Demand Ephemeral Environment, Preview Environment pattern Developer Environments A full running instance of the system created automatically per branch or pull request and destroyed when it merges.
Developer Portal tool APIs as Products The self-service surface where consumers discover APIs, read documentation, obtain credentials and test calls — the main determinant of adoption.
Device Class Baseline Reference Device, Slow-Tier Baseline practice Web Performance Budgets A named device and network profile, chosen from the slow end of your real user population, against which every performance budget and acceptance test is measured - so that "fast" means fast for the users who a…
Device Group Rollout practice Fleet Management Applying configuration or firmware to a fleet in ordered cohorts with health checks between them, because a bad change applied to everything at once has no remedy.
Device Identity concept Device Identity Establishing and maintaining a trustworthy identity for each device in a fleet — including the parts that must work for a decade without physical access.
Device Provisioning practice Device Provisioning Giving a device a unique cryptographic identity and its initial configuration in a way that scales to millions and survives a hostile supply chain.
Device Shadow Digital Twin, Reported and Desired State pattern Digital Twin A cloud-side representation of a device's last reported state and its intended state, letting applications interact with devices that are asleep or offline.
Device Telemetry at Scale concept Device Telemetry at Scale The volume problem created by many devices each emitting small frequent messages, where the answer is filtering at the edge rather than ingesting everything.
Device-Side Refusal Local Precondition Check, The Device Decides concept OTA Updates The rule that a device must refuse an unsafe instruction regardless of what the server commanded, because the server does not know the device's physical state.
Diagnostic Radius Failure Blast Radius, Signal Narrowness concept Test Pyramid Shapes The number of distinct causes consistent with a test's failure - the property that actually separates the layers of a test suite and decides what a red build costs to investigate.
Diagram Altitude concept Architecture Diagrams The level of abstraction a diagram commits to, and the rule that mixing levels in one picture makes it useless to every audience.
Diagram Maintenance Economics Which Diagrams to Keep, Stale Diagram Cost concept C4 Model The rule that a diagram earns its maintenance cost only when it explains something hard to derive from source - which is why structure diagrams below the container level should be generated or absent.
Diagram Notation Consistency practice Architecture Diagrams Using shapes, colours, line styles and arrow directions to mean the same thing across every diagram, and stating what they mean on the diagram itself.
Diagram Provenance Diagram Dating, Generated-From Line practice Data-Flow Diagrams A line on every diagram stating what it was generated from, when, and when it will next be refreshed, so readers can weigh its accuracy instead of assuming it.
Diagrams as Code Architecture as Code, Textual Diagram Model practice Architecture Diagrams Keeping architecture pictures as text in the same repository as the code they describe, so a structural change and its diagram are reviewed in one pull request instead of drifting apart.
Differencing Attack Query Differencing, Reconstruction Attack concept Data Sharing & Clean Rooms Inferring an individual's data from the difference between two permitted aggregate results - the reason that returning only aggregates is not by itself a privacy guarantee.
Differential Privacy Budget concept Privacy-Enhancing Technologies The cumulative privacy loss permitted across all queries against a dataset, which must be tracked and exhausted rather than applied per query.
Differential Profiling Profile Diffing, Comparative Profiling practice Profiling Comparing two normalised profiles of one workload to attribute a performance change to a specific code path - the step that turns "release 2.4 is slower" into a named function, and the normalisation errors tha…
Differentiation Test practice Build vs Buy The question of whether a capability is a source of competitive advantage, used as the primary filter in build-versus-buy decisions.
Digital Sovereignty concept Digital Sovereignty Requirements that data and the ability to operate on it remain under a jurisdiction's control — a stronger and more architecturally demanding constraint than residency.
Dimensional Model Star Schema, Kimball Model pattern Dimensional Modelling Organising analytical data as fact tables of measurements surrounded by dimension tables of descriptive context.
Disagree and Commit Principled Dissent, Recorded Objection, Commit With Trigger practice Handling Disagreement Recording a dissent with its reasoning and a monitorable revisit trigger, then executing the chosen approach wholeheartedly - which preserves both the organisation's ability to move and the record needed to learn.
Disaster Recovery DR practice Reliability & Resilience The plan and capability for restoring service after an event that takes out a whole site, region or system.
Discord's Message Store Migrations case-study Data Architecture Discord moved from MongoDB to Cassandra to ScyllaDB as message volume grew from millions to trillions, each time for a specific and different reason.
Discord: Hot Partitions at Trillions of Messages Discord Message Storage case-study Partitioning & Sharding Discord partitions messages by channel and time bucket, because a single very busy channel would otherwise concentrate load on one partition.
Disposition Decision practice The Six Rs Choosing one of the standard migration treatments for each application, on the basis of its value, condition and the constraint that is actually binding.
Distributed Locks in Practice Lease, Mutual Exclusion pattern Distributed Locking Why lease-based locking is unsafe without fencing, when locks are unavailable entirely, and the partitioning alternative that removes the problem.
Distributed Monolith concept Microservices A system split into services that must still be deployed, changed and operated together, incurring distribution costs without independence.
Distributed Trace concept Distributed Tracing A causally-linked record of one request's path across services, composed of spans that carry timing, attributes and parent relationships.
Distributed Tracing tool Observability Following one logical request across every service it touches by propagating a shared trace identifier and recording timed spans.
Distributed Tracing in Practice tool Distributed Tracing Following one request across every service it touches — the only tool that answers "where did the time go" in a distributed system.
Diátaxis Framework Diátaxis, Four-Mode Documentation practice Documentation Practice A placement rule for technical documentation that separates four reader needs - tutorial, how-to, reference and explanation - so one page serves one need instead of mixing all four and serving none.
DNS Domain Name System protocol Networking The distributed directory that resolves names to addresses, and a surprisingly load-bearing part of most architectures.
DNS Resolution Chain concept DNS The sequence of lookups from browser cache through OS cache, recursive resolver, root, TLD and authoritative server that turns a name into an address.
DNS TTL concept DNS The time a DNS record may be cached, and a value that resolvers, operating systems and applications honour inconsistently.
DNS TTL Strategy practice DNS Choosing record lifetimes to balance failover speed against query volume, knowing that resolvers and clients do not reliably honour them.
Document Store tool NoSQL Stores A store that keeps semi-structured documents — typically JSON — retrievable by key and queryable by their contents.
Documentation Decay concept Documentation Practice The tendency of written documentation to become inaccurate faster than it is updated, making stale documentation actively more harmful than none.
Documentation Half-Life Doc Decay, Staleness Rate concept Architecture Documentation The observation that architecture documentation decays in proportion to how much it restates current structure, and that the artefacts which survive are the ones that were always historical.
Documentation Practice practice Documentation Practice Writing what will be read, keeping it true, and deliberately not writing the rest.
Domain Boundaries from the Business practice Domain Boundaries Deriving service boundaries from the language and decisions of the business, rather than from data structure or team structure.
Domain Data Ownership concept Data Mesh Making the team that generates data accountable for publishing it fit for others to use, rather than handing raw extracts to a central team.
Domain Publishing Readiness Data Product Admission Bar, Domain Onboarding Gate practice Data Mesh The small set of capabilities a domain team must demonstrably have before it is allowed to publish a data product, which is what separates decentralised ownership from renaming existing teams as domains.
Domain-Driven Design DDD practice Software Architecture Modelling software around the business domain, with boundaries drawn where the language of the business changes.
DoorDash Dispatch: Matching as an Optimisation Problem Deep Red, Assignment Optimisation case-study Streaming & Real-Time Data Assigning deliveries greedily to the nearest driver is locally sensible and globally poor, so the assignment is batched and solved as an optimisation.
DoorDash: Decomposing a Python Monolith DoorDash Microservices Migration case-study Service Boundaries DoorDash moved off a Python monolith as growth made deployment risk and scaling limits unmanageable, and used a facade to migrate incrementally.
DORA Metrics metric DORA Metrics Four measures of software delivery — deployment frequency, lead time, change failure rate, time to restore — that resist gaming better than most.
Drift Reconciliation Post-Incident Codification, Managed Divergence practice Infrastructure as Code Treating divergence between declared and actual infrastructure as an expected condition with an owned resolution path, rather than as a violation to be automatically reverted.
Dropbox's Move Off S3 Magic Pocket case-study Cost & FinOps Dropbox moved the majority of its file storage off Amazon S3 onto custom infrastructure, reporting savings that its S-1 filing put at roughly $75 million over two years.
Dual Write pattern Data Migration Strategies Writing the same change to both the old and new stores during a migration, and the reconciliation that makes it trustworthy.