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
Big Ball of Mud	concept	Modularity	A system with no discernible structure, where every change requires understanding everything - usually the result of many locally rational decisions.
Billable-Event Metering Contract-Aligned Metering, Obligation-Point Metering	practice	Licence & Vendor Costs	Recording the event a contract actually charges for at the point in the system where that obligation is created, rather than inferring it from delivery telemetry that caching and retries make unreliable.
Bin-Packing Efficiency Packing Density, Requested-to-Allocatable Ratio	metric	Rightsizing	The share of purchased node capacity that scheduled workloads have actually reserved, which is the missing link between a rightsizing campaign and the invoice it was supposed to reduce.
Binary Serialisation	concept	Message Formats	Encoding messages compactly using a schema rather than as self-describing text, trading readability for size and parse speed.
Binding Constraint Limiting Stage, Active Constraint	concept	Constraint Thinking	The one resource in a chain whose capacity sets the throughput of the whole chain - so that investment anywhere else buys idle capacity rather than output.
Blameless Postmortem Learning Review, Incident Retrospective, Non-Attributive Analysis	practice	Postmortems	An incident analysis structured so that participants can disclose what actually happened without personal risk - which is a technical requirement for accurate information, not a cultural courtesy.
Blameless Postmortem	practice	Reliability & Resilience	An incident review that seeks the systemic conditions that made a failure possible, explicitly excluding individual fault.
Blast Radius Failure Scope, Impact Radius, Containment Boundary	concept	Fault Isolation	The set of users, tenants, regions or services that a single failure can affect - the quantity that distinguishes an incident from a catastrophe, and the one that architecture can most directly control.
Blast Radius	concept	Cloud Architecture	The set of things that break, or become reachable, when one component fails or is compromised.
Blast Radius Analysis	practice	Fault Isolation	Determining, for each component, exactly what fails and who is affected when it fails completely.
Blast Radius Reduction	practice	Cloud Architecture	The set of deliberate partitions — accounts, regions, zones, cells, tenants, deployment stages — that bound how far any single failure or compromise can reach.
Blast Radius Staging Graduated Rollout, Progressive Shedding	practice	Failover	Applying a change or a traffic shift in increasing increments gated on health, so that a wrong decision affects a bounded population before it affects everyone.
Block Storage Persistent Disk, EBS	concept	Cloud Storage	A virtual disk attached to one instance at a time, presented as raw blocks and formatted with a filesystem — the storage databases and stateful workloads run on.
Bloom Filter	tool	Data Architecture	A compact probabilistic structure that answers "is this key definitely absent, or possibly present?" — no false negatives, tunable false positives.
Bloom Filter Cache Guard	pattern	Caching Strategies	Placing a Bloom filter in front of an expensive lookup so that keys which certainly do not exist never reach it.
Blue-Green Database Schema	pattern	Release Strategies	The constraint that makes fast rollback actually work — both application versions must be able to run against one schema at the same time.
Blue-Green Deployment	pattern	Deployment Strategies	Two complete production environments where traffic is switched from the old to the new in one step, and back just as fast.
Booking.com's Experimentation Platform	case-study	Business Architecture	Booking.com runs over a thousand concurrent experiments and treats the ability to test any change safely as a platform capability rather than a product feature.
Bootstrap Kill Switch Boot-Path Flag, Safe Mode Configuration	pattern	Client Feature Flags	A configuration value read from local storage before any application code initialises, paired with a launch-failure counter, so a client that crashes during start-up can still be disabled and recovered.
Bottleneck	concept	Bottleneck Analysis	The single resource that limits system throughput, such that improving anything else produces no gain.
Bottleneck Analysis	practice	Bottleneck Analysis	Finding the single resource that limits the system, because improving anything else changes nothing.
Bottom Line Up Front	practice	Written Communication	Placing the conclusion and the requested action in the first lines, on the assumption that most readers will not reach the end.
Boundary Reversal Asymmetry Split Reversal Cost, Asymmetric Boundary Error	concept	Service Boundaries	The fact that a boundary drawn too coarse is cheap to split later while one drawn too fine is expensive to merge, which makes the coarse error the right default when evidence is thin.
Boundary Traffic Cost Chattiness Tax, Decomposition Data Cost, Per-Hop Cost	concept	Coupling	The recurring cost of the data and coordination that cross a component boundary - paid on every request forever, and the number that decides whether a decomposition is affordable rather than merely tidy.
Boundary Volatility Test	practice	Service Boundaries	Evaluating a proposed service boundary by asking whether the things on either side change for different reasons and at different rates.
Boundary-Crossing Count Teams Per Feature, Coordination Metric	metric	EA Metrics	The number of teams that must change to deliver a median feature - the most revealing and least used architecture metric, because it measures whether boundaries match the way work arrives.
Bounded Context	concept	Bounded Contexts	A boundary within which a model and its vocabulary are internally consistent, and outside which the same words may legitimately mean something different.
Bounded Queue	pattern	Backpressure & Flow Control	A queue with a maximum depth, which converts unbounded latency growth into an explicit rejection you can control.
Branch by Abstraction	pattern	Refactoring	Making a large change incrementally on the trunk by introducing an abstraction over the old implementation, building the new one behind it, then removing the abstraction.
Branch Lifetime	metric	Trunk-Based Development	How long a branch lives before being merged, which determines integration pain and is the practical measure of whether integration is continuous.
Break-Glass Access Emergency Access, Just-in-Time Elevation	practice	Identity & Access Management	A pre-agreed, heavily audited path to elevated privilege for emergencies, replacing standing administrative access.
Break-Glass Change Ratio Emergency Change Rate, Bypass Ratio	metric	Change Advisory vs Automated Gates	The share of production changes that took the emergency path instead of the gated one, which measures how much of the change population a control actually covers.
Breaking-Point Testing Test to Failure, Constraint Discovery	practice	Load Testing	Pushing a load test past the target until the system fails, because the purpose of a load test is to locate the constraint and the failure mode rather than to confirm a number.
Broker and Mediator Topology	pattern	Event-Driven Architecture	Two ways of organising an event-driven system — components reacting independently to a shared channel, or a central component coordinating a defined sequence.
Bronze Layer Contract	concept	Medallion Architecture	What the raw landing zone promises and refuses to promise — a faithful replayable copy of the source, with no correction applied.
Brownout	pattern	Load Shedding	Deliberately reducing the quality or completeness of every response under load, rather than serving some requests fully and rejecting others.
Budget Guardrail	practice	Cost Governance	An automated control that constrains or alerts on spend before an invoice arrives, rather than reporting overspend after the fact.
Build Attestation	concept	Supply-Chain Provenance	A signed statement about how an artifact was produced — by which builder from which source — that a deployment gate can verify rather than trust.
Build Graph Scoping	concept	UI Monorepo Strategy	Determining which packages a change actually affects, so a monorepo builds and tests a subset rather than everything on every commit.
Build Provenance Attestation, SLSA Provenance, Artefact Lineage	pattern	Supply Chain Security	A signed, verifiable record of which source, builder and inputs produced a given artefact, checked at deployment - which makes the integrity of the build system testable rather than assumed.
Build Provenance Artefact Attestation, SLSA Provenance	practice	Supply Chain Security	A signed, verifiable statement of what was built, from which source, by which builder, with which dependencies - so a consumer can check that an artefact corresponds to reviewed source.
Build Reproducibility Reproducible Build, Deterministic Build	practice	Build Reproducibility	The same source input produces a bit-for-bit identical artifact, on any machine, at any time.
Build versus Buy	practice	Build vs Buy	Whether to build a capability or acquire it — decided primarily by whether the capability differentiates, not by whether you could build it.
Build vs Buy	concept	Architecture Decision-Making	The choice between developing a capability in-house and acquiring it, decided on differentiation and total cost rather than on feature lists.
Build-Versus-Buy Crossover Point In-House Crossover, Insourcing Threshold	concept	Trade-off Analysis	The set of conditions under which operating a capability yourself beats paying a vendor - all of which must hold, because the standing cost of self-operation is annual while the exit cost of a vendor is paid once.
Build-vs-Buy Total Cost	practice	Build vs Buy	Comparing a purchased solution against building one on the full lifetime cost, including the maintenance and opportunity costs that estimates omit.
Bulk and Batch API Design	practice	REST Design	Endpoints that accept many items in one call, and the partial-failure semantics that make them either useful or dangerous.
Bulkhead	pattern	Bulkheads & Isolation	Partitioning resources so that exhaustion in one area cannot consume the capacity another area depends on.
Bulkheads in Practice Resource Partitioning, Compartmentalisation	pattern	Bulkheads & Isolation	Partitioning resources so one dependency's failure cannot consume what another needs, and the aggregate-sizing mistake that moves the exhaustion one layer down.
Burn Rate Alerting Multi-Window Multi-Burn-Rate, SLO Burn Alert, Budget Consumption Alert	pattern	Alerting	Alerting on how fast an error budget is being consumed, across multiple time windows simultaneously, so that a sudden outage pages immediately while a slow erosion opens a ticket.
Burst Capacity Cloud Bursting, Overflow Capacity	concept	Cloud Architecture	Capacity acquired quickly for short-lived demand above the baseline, deliberately priced higher than owned capacity in exchange for immediate availability.
Burstable Instance T-series, B-series	concept	Compute Models	An instance that provides a low baseline CPU allocation and accrues credits while idle, spendable for short periods of full performance.
Business Capabilities	concept	Business Capabilities	What the business does, expressed independently of how it does it — the most stable frame available for drawing system boundaries.
Business Capability	concept	Business Architecture	What a business does, expressed stably and independently of how it currently does it or who is responsible.
Business Case Structure	practice	Business Cases	The argument format that gets technical investment funded — problem, options, quantified benefit, cost, risk and a recommendation.
Business Cases	practice	Business Cases	The argument that an investment is worth making — where architects supply the cost, risk and option value rather than the enthusiasm.
Business Continuity	practice	Business Continuity	Keeping the business operating through disruption — a broader discipline than disaster recovery, and one that includes not using the system at all.
Business Correlation Identifier Domain Trace Key, Entity Correlation	practice	Correlation IDs	A domain identifier - shipment, order, trip, claim - carried on every log line, event, job and external call, answering the question distributed tracing cannot: what happened to this thing, over days, across s…
Business Domain Boundary	concept	Domain Boundaries	A division of the business into areas with distinct language, ownership and rates of change, used as the primary input to system and team boundaries.
Business Glossary	tool	Business Glossary	An agreed set of business term definitions, owned by the business and linked to the physical data assets that implement them.