Terminology

454 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 areas454 Architecture Fundamentals16 Distributed Systems73 Data Architecture71 Cloud Architecture55 Networking13 API & Integration Architecture17 Reliability & Resilience16 Observability14 Performance & Capacity Engineering13 Security Architecture50 Cost Architecture & FinOps12 Business Architecture9 Architecture Communication8 Enterprise Architecture8 Legacy Modernization11 AI-Era Architecture15 Software Architecture & Engineering19 Architecture Patterns15 Architecture Decision-Making11 The Architect's Meta-Skills8

Kind Any concept166 practice107 pattern93 case-study26 tool26 protocol22 metric14

454 terms shown.

Term	Kind	Topic	What it is
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.
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.
Admission Control	pattern	Load Shedding	Deciding at the edge whether to accept a request at all, based on current capacity, before any work is done on it.
AI Gateway	pattern	AI-Era Architecture	A shared proxy in front of model providers that centralises routing, keys, quotas, caching, logging and safety policy.
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.
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.
Anti-Corruption Layer ACL	pattern	Legacy Modernization	A translation layer that converts a legacy or external system's model into your own, so its concepts do not leak into your domain.
Anycast	concept	Networking	Advertising the same IP address from many locations, so the network routes each client to the topologically nearest one.
API Gateway	pattern	API & Integration	A single entry point in front of a set of services that handles authentication, rate limiting, routing and protocol translation.
Application Discovery	practice	Cloud Migration	Establishing what applications exist, what they depend on, who owns them and whether anyone uses them — the step whose absence makes every later step a guess.
Application Performance Monitoring APM	tool	Observability	Instrumentation inside the application that attributes latency and errors to specific code paths, queries and dependencies.
Application Portfolio Management APM, Application Rationalisation	practice	Enterprise Architecture	Maintaining an inventory of every application with its owner, cost, business value and technical health, and using it to decide what to invest in, replace or retire.
Architectural Driver	concept	Architecture Fundamentals	The small subset of requirements and constraints that actually shape the structure of the system.
Architecture Cost Model	practice	Cost & FinOps	A calculation, made during design, of what an architecture will cost to run at expected and at peak volume.
Architecture Decision Log ADR Log, Decision Register	practice	Architecture Communication	The ordered, immutable collection of a system's decision records, read as a history rather than as a specification.
Architecture Decision Record ADR	practice	Architecture Decision-Making	A short, immutable document capturing one architectural decision, its context, the alternatives, and its consequences.
Architecture Principle	practice	Architecture Fundamentals	A durable, agreed rule that constrains design decisions in advance, stated with its rationale and its implications.
Architecture Review Board ARB, Design Authority	practice	Enterprise Architecture	A forum that reviews significant designs against standards, risks and strategy before commitment.
Architecture Style	concept	Architecture Fundamentals	A named, coarse-grained way of organising a whole system, as distinct from a pattern that solves one recurring problem inside it.
Architecture Trade-off Analysis Method ATAM	practice	Architecture Decision-Making	A structured evaluation that scores an architecture against prioritised quality-attribute scenarios and identifies the points where those attributes conflict.
Artifact Signing	practice	Supply Chain Security	Cryptographically signing build outputs so that deployment can verify what is being run was produced by the expected pipeline from the expected source.
At-Least-Once Delivery	concept	Messaging & Queues	The guarantee that a message will be delivered, possibly more than once — the practical default in every distributed messaging system.
Atomic Commit Protocol	concept	Distributed Transactions	Any protocol ensuring that several participants reach the same decision to commit or abort — and a problem provably unsolvable with certainty in an asynchronous system with failures.
Attack Surface	concept	Threat Modelling	The complete set of points where an untrusted actor can interact with a system — and the quantity that reduction genuinely reduces risk.
Auditability	concept	Security Architecture	The ability to reconstruct who did what, to which resource, when, and from where — reliably enough to be relied upon after the fact.
Authentication AuthN	concept	Security Architecture	Establishing who a principal is, to a defined level of confidence.
Authorization AuthZ	concept	Security Architecture	Deciding whether an authenticated principal may perform a specific action on a specific resource.
Authorization Code Flow with PKCE PKCE	protocol	OAuth 2.0 & OIDC	The OAuth flow recommended for all client types, in which an authorisation code is exchanged for tokens using a proof key that binds the exchange to the original requester.
Autoscaling	pattern	Cloud Architecture	Adding and removing capacity automatically in response to a demand signal, to track load without paying for peak all the time.
Availability Calculation	concept	Reliability & Resilience	Deriving a system's availability from its components, remembering that dependencies in series multiply.
Availability Zone AZ	concept	Cloud Architecture	One or more physically separate data centres inside a cloud region, with independent power, cooling and network, connected by low-latency links.
Backend for Frontend BFF	pattern	Architecture Patterns	A separate, narrow backend per client experience, which aggregates and reshapes downstream services for exactly that client's needs.
Backfill	practice	ETL & ELT	Re-running a pipeline over historical periods to populate new data or correct a past error, and the operation that proves whether a pipeline is well designed.
Backpressure	concept	Distributed Systems	A mechanism by which a component under load tells its callers to slow down, rather than accepting work it cannot complete.
Backup Strategy 3-2-1 Rule	practice	Cloud Architecture	A plan for what is copied, how often, where to, how long it is kept, and — the part that decides whether it is real — how the restore is verified.
Backward Compatibility	concept	API & Integration	The property that a new version of a producer continues to work with clients written against the old version.
Blameless Postmortem	practice	Reliability & Resilience	An incident review that seeks the systemic conditions that made a failure possible, explicitly excluding individual fault.
Blast Radius	concept	Cloud Architecture	The set of things that break, or become reachable, when one component fails or is compromised.
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.
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	Software Architecture	Running two identical production environments and switching traffic from the old one to the new one in a single cut, with the old kept warm for rollback.
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.
Bounded Queue	pattern	Backpressure & Flow Control	A queue with a maximum depth, which converts unbounded latency growth into an explicit rejection you can control.
Brownout	pattern	Load Shedding	Deliberately reducing the quality or completeness of every response under load, rather than serving some requests fully and rejecting others.
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.
Bulkhead	pattern	Distributed Systems	Partitioning resources so that exhaustion caused by one dependency or tenant cannot starve the others.
Burn Rate Alerting	practice	SLO Monitoring	Paging when the error budget is being consumed fast enough to matter, rather than when a component crosses a threshold.
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 Capability	concept	Business Architecture	What a business does, expressed stably and independently of how it currently does it or who is responsible.
Byzantine Fault	concept	Failure Modes	A failure in which a component behaves arbitrarily or deceptively — returning wrong results rather than stopping — as distinct from simply crashing.
C4 Model	practice	Architecture Communication	A set of four nested diagram levels — context, container, component, code — that keeps each diagram at one consistent level of abstraction.
Cache Invalidation	concept	Data Architecture	The problem of removing or refreshing cached data when the underlying source changes, and the reason caching is harder than it looks.
Cache Penetration	concept	Cache Invalidation	Repeated lookups for keys that do not exist, which miss the cache every time by definition and pass straight through to the store.
Cache Stampede Dog-piling, Thundering Herd on Cache	concept	Cache Invalidation	Many concurrent requests missing on the same expired key and all recomputing it simultaneously, converting one expiry into a load spike.
Caching Strategy	pattern	Performance & Capacity	The chosen pattern for how a cache is populated, read and invalidated — cache-aside, read-through, write-through or write-behind.
Canary Release	pattern	Software Architecture	Routing a small fraction of traffic to a new version, watching its metrics, and expanding or rolling back based on what they show.