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Terminology

2185 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 areas2185 Architecture Fundamentals77 Distributed Systems107 Data Architecture110 Cloud Architecture89 Networking88 API & Integration Architecture82 Reliability & Resilience75 Observability70 Performance & Capacity Engineering72 Security Architecture81 Cost Architecture & FinOps66 Business Architecture67 Architecture Communication67 Enterprise Architecture66 Legacy Modernization66 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 concept785 practice729 pattern362 metric125 case-study77 tool62 protocol45

2185 terms shown.

Term Kind Topic What it is
A/B Partition Update Dual-Bank Update, Seamless Update pattern OTA Updates Writing a new device image to an inactive partition and switching to it only after verification, so that a failed update falls back to the known-good image instead of bricking the device.
A/B Partition Update pattern OTA Updates Writing firmware to an inactive partition and switching on next boot, so a failed update falls back to the previous image rather than bricking the device.
Absence-As-Delete Sync Full-Sync Delete Semantics, Destructive Sync concept Reverse ETL A synchronisation mode that treats a record's absence from the source query as an instruction to remove or clear it downstream - so any query returning fewer rows becomes a mass deletion in a live operational …
Abstraction concept Architecture Fundamentals Exposing what a component does while hiding how it does it, so callers depend on the contract rather than the mechanism.
Abstraction and Encapsulation concept Abstraction & Encapsulation Hiding mechanism behind a contract so the mechanism can be replaced — and the discipline of not letting the mechanism leak through the contract.
Abstraction Level Discipline practice C4 Model Keeping each diagram to a single level of zoom, and providing separate diagrams for each level rather than one diagram attempting all of them.
Abuse Case Misuse Case concept Communicating Threat Models A use case written from the attacker's side - a hostile actor plus the interaction that achieves their goal - which engineers can refute or fix, unlike a likelihood-impact score which they can only dispute.
Access Geography Access as Transfer, Remote Viewing concept Cross-Border Transfer The recognition that viewing data from another jurisdiction is a cross-border transfer, which makes access control and the location of the people using it a transfer control.
Access Pattern Driven Modelling practice SQL vs NoSQL Designing the data model from the queries the application must serve, rather than from an abstract normalised representation of the entities.
Access Pattern Skew Popularity Skew, Zipf Distribution concept Caching for Performance The uneven distribution of requests across keys - which determines whether caching helps at all, and which synthetic load tests systematically fail to reproduce.
Accessibility Architecture Structural Accessibility, Accessibility by Construction practice Accessibility Architecture Placing conformance in the components routing and release pipeline that every team already uses - so accessibility is maintained by construction rather than recovered by an audit each year.
Accessibility Regression Gate Accessibility CI Gate, Conformance Gate practice Accessibility Architecture An automated check plus a named manual pass in the release pipeline that blocks a change which breaks accessibility, so conformance is maintained by the build rather than recovered by an annual audit.
Accessibility Testing a11y Testing, WCAG Testing practice Accessibility Testing Verifying that an interface is usable by people with disabilities, through automated checks, assistive technology testing and structural review.
Accessible Component Contract Component Accessibility Contract, Design System Accessibility Guarantee pattern Accessibility Testing A published, tested statement of a shared component's keyboard model, roles, names and announced states, so that accessibility is verified once where the component is built rather than re-audited in every prod…
Accidental vs Essential Complexity concept Architecture Fundamentals Essential complexity comes from the problem and cannot be removed; accidental complexity comes from your solution and usually can.
Account Vending practice Landing Zones Automated creation of new cloud accounts pre-configured with the organisation's networking, identity, logging, guardrails and cost allocation.
Active-Active vs Active-Passive concept Multi-Region Architecture Whether all regions serve traffic simultaneously, or one serves while another waits to take over — a choice about which failure mode you would rather have.
Adapter Conformance Suite Port Conformance Tests, Shared Adapter Test Suite pattern Hexagonal Architecture One test suite written against a port and run against every implementation including the in-memory fake, so the fake cannot promise behaviour the real adapter does not deliver.
Adaptive Admission Level Priority Admission Threshold, Collaborative Load Shedding pattern Queueing Theory A load-dependent priority threshold that a service publishes back to its callers, so requests that would be rejected downstream are never sent and upstream work is not wasted.
Additive-Only Evolution Non-Breaking Change Discipline, Tolerant Reader Contract concept API Versioning Establishing the compatibility contract before the first release - unknown fields ignored, unknown enum values defaulted - so that most future change requires no version at all.
Administrative Path Blindness Support Tool Gap, Internal Access Blind Spot concept Authorization The pattern where the customer-facing data path is rigorously access-controlled while internal dashboards, support tools, analytics jobs and exports have unrestricted access - protecting against the wrong adversary.
Admission Control practice Load Shedding Deciding at the entrance whether to accept a request at all, based on whether the system can complete it within its deadline.
Admission Policy pattern Policy as Code A rule evaluated at the moment a resource is created or changed, which rejects the request rather than reporting on it afterwards.
Admission Queue Virtual Waiting Room, Login Queue, Front-Door Queue pattern Performance & Capacity Holding excess arrivals in an explicit, communicated queue and admitting them at a rate the system can serve - converting an overload failure into a wait, which is a far better outcome and must be built in advance.
Adoption Barrier Diagnosis Why Teams Built Their Own, Duplication Root Cause practice Application Rationalisation Treating duplicated internal systems as evidence that the shared option was harder to adopt than to rebuild - and fixing that before consolidating, or the duplication returns.
Adoption Curve metric Platform Adoption The proportion of teams actually using a platform capability over time, which is the only honest measure of whether the platform is working.
ADR Lifecycle practice Decision Practice The states an architecture decision record moves through — proposed, accepted, superseded, deprecated — and the discipline that keeps the set trustworthy.
Adversarial Evaluation practice Model Evaluation & Red-Teaming Deliberately attempting to make a model behave badly, because a probabilistic system with no fixed expected output cannot be verified by conventional testing.
Advisory Review Model practice Architecture Review Boards Running architecture review as a consulting service that improves designs rather than as an approval gate that permits them.
Afferent and Efferent Coupling metric Coupling The counts of components depending on a module and of components it depends upon, used together to identify which parts of a system are expensive to change.
Agent Handoff pattern Multi-Agent Systems The transfer of a task and its context from one specialised agent to another, and the point at which multi-agent systems most often lose information.
Agent Loop concept Agent Architectures The cycle in which a model observes state, selects an action, executes a tool and observes the result, repeating until a goal or a limit is reached.
Agent Tool Authorisation pattern Tool Calling Enforcing that a tool invoked by a model executes with the requesting user's permissions rather than the application's, and that consequential actions require confirmation.
Agent Transcript Compaction Loop History Summarisation, Working Memory Compaction pattern Agent Architectures Replacing the resolved middle of a long agent loop with a short summary while preserving the original goal and constraints verbatim, so token cost stops growing quadratically and late steps still follow early …
Aggregate pattern Domain-Driven Design A cluster of objects treated as a single unit for data changes, with one root through which all modification passes, defining the consistency boundary.
Aggregation Threshold Policy Minimum Cohort Rule, k-Threshold Output Policy pattern Data Sharing & Clean Rooms A rule that only returns results computed over at least a minimum number of subjects, plus limits on overlapping queries, so that shared analytics cannot be resolved back to an individual.
AI Gateway pattern AI-Era Architecture A shared proxy in front of model providers that centralises routing, keys, quotas, caching, logging and safety policy.
AI Gateway Pattern LLM Proxy, Model Router pattern AI Gateways A single control point through which all model calls pass, providing routing, cost control, caching, logging, guardrails and provider abstraction.
AI Risk Tiering practice AI Risk Tiering Classifying AI systems by potential harm so that governance effort is proportionate, rather than applying the same controls to every use.
Airbnb Minerva: One Definition of a Metric Minerva Metrics Platform case-study Semantic Layer Airbnb built a central metrics platform because the same business question was producing different answers depending on which dashboard you opened.
Airbnb's Service-Oriented Migration case-study Legacy Modernization Airbnb decomposed a large Rails monolith by first extracting a unified data-access layer, so that services were built on owned data rather than on shared database tables.
Airbnb: Monorail to Service-Oriented Architecture Airbnb SOA Migration case-study Application Decomposition Airbnb decomposed a large Rails monolith into services, and the difficult part was data ownership rather than code extraction.
Airflow: A Scheduler Born From Pipeline Sprawl Apache Airflow case-study Workflow Schedulers Airbnb built Airflow because cron cannot express dependencies, and a data platform's failures are mostly dependency failures.
Alert Actionability metric Alert Fatigue The proportion of alerts that result in a human taking action, used as the primary quality measure of an alerting system.
Alert Fatigue concept Observability The desensitisation that follows from alerts that are frequent, non-actionable, or not tied to user impact — after which real alerts are missed too.
Alert Fatigue in Practice concept Alert Fatigue The state in which alerts are ignored because most of them do not matter — a reliability failure caused by monitoring rather than prevented by it.
Alert on Symptoms Symptom-Based Alerting concept Alerting Paging on user-visible impact rather than on internal conditions that may or may not cause it.
Amazon 2002: The API Mandate Bezos Mandate case-study API & Integration A directive that all teams expose functionality only through service interfaces, with no back doors, is widely credited with making both Amazon's architecture and AWS possible.
Amazon Dynamo: Always Writeable Dynamo Paper case-study Consistency Models Amazon chose an always-writeable shopping cart with application-level conflict resolution, accepting merge complexity to guarantee that "add to cart" never fails.
Amazon Prime Video: Serverless Back to a Monolith Prime Video Audio/Video Monitoring case-study Monolith vs Microservices A distributed serverless pipeline was consolidated into a single process, reducing cost by over 90% — for one component, for specific reasons that do not generalise.
Ambassador Pattern pattern Sidecar & Ambassador A helper process that handles outbound network communication on behalf of an application, adding retries, routing, security and telemetry without changing it.
Ambiguity Tolerance concept Handling Ambiguity The capacity to make progress on a problem before it is fully specified, which is the normal condition of architectural work.
Ambiguous Outcome Unknown State, Indeterminate Result concept Timeouts & Deadlines The state a system is in when a call times out - not failure, but unknown - and the design obligation to have somewhere to put it.
Amdahl's Law concept Profiling & Optimisation The limit on speedup from optimising or parallelising part of a system, set by the proportion of work that remains unchanged.
Amortised Cost View Effective Rate Reporting, Commitment-Adjusted Showback practice Cost Allocation Reporting each team's spend at the effective discounted rate spread across a commitment term, so a team's number moves only when its own usage moves rather than when the finance department buys something.
Anaemic Domain Model concept Domain-Driven Design Objects that hold data with no behaviour, leaving business rules scattered across service classes where they are duplicated and inconsistently applied.
Analytical Estate Topology concept Data Platform Architecture The full picture of where analytical data lands, is transformed and is served, including the paths that bypass the intended one.
Analytics Cost Control practice Analytics Cost Control The set of design and operational choices that determine whether an elastic data platform costs a predictable amount or an alarming one.
Anomaly Retention Keep the Weird Records, Realistic Test Data practice Test Data Management Preserving the malformed, historical and hand-fixed records when producing test data - because they are precisely what breaks migrations and new code paths, and a sanitising process removes exactly what made t…
Anti-Corruption Layer ACL pattern Anti-Corruption Layer A translation boundary that keeps another system's model — usually a legacy or vendor one — from leaking into your domain.