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

785 terms shown.

Term	Kind	Topic	What it is
Beacon Survivorship RUM Survivorship Bias, Abandonment Bias	concept	Real User Monitoring	The bias in field performance data caused by users abandoning a page before the measurement beacon is sent - so the slowest sessions are excluded and the metric improves as the experience gets worse.
Behavioural Specification Gap Structure-Only Reference, Diagram-Level Standard	concept	Reference Architectures	The omission in a reference architecture that specifies components and call directions but not behaviour under failure - so every team that complies invents the same timeout and retry defaults and produces the…
Best Effort Delivery	concept	Push & Background Work	The guarantee push notification services actually offer — which is none — and the design consequences of building on a channel that may silently drop.
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.
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.
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.
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.
Bottleneck	concept	Bottleneck Analysis	The single resource that limits system throughput, such that improving anything else produces no gain.
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.
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.
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.
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 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.
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 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 Processes	concept	Business Processes	The sequences of activity that exercise capabilities — where handoffs, exceptions and manual steps reveal what the architecture must support.
Bytes Scanned Scan Volume, Data Processed	concept	Analytics Cost Control	The volume of data a query reads - which in consumption-priced analytical systems is both the performance limit and the bill, making layout a cost control.
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.
Cache Hit Ratio Economics	concept	Caching for Performance	The non-linear relationship between cache hit rate and backend load, which determines whether a cache improvement is worth making.
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 Thundering Herd, Dog-Piling	concept	Caching for Performance	The surge of identical expensive requests to the origin when a popular cache entry expires and many concurrent callers all miss at once.
Canonical Data Model Common Data Model, Enterprise Data Model	concept	Integration Patterns	One shared representation that every producer maps into and every consumer reads from, trading N×M translations for a single model that grows monotonically and can never be trimmed.
CAP Theorem Brewer's Theorem	concept	Distributed Systems	During a network partition a distributed system must choose between consistency and availability; it cannot have both.
Capability Confinement Least-Privilege Agents, Trust Domain Separation, Action Authorisation	concept	Prompt Injection Defence	Limiting what an agent is authorised to do rather than trying to prevent it from being misled - because a model cannot reliably distinguish instructions from data, so the security boundary must sit outside it.
Capability Decomposition Depth Capability Map Depth, Capability Level Choice	concept	Capability Maps in EA	The level at which a capability map stops describing what a business does and starts describing how it is currently organised - the point past which it must be redrawn at every reorganisation and its refresh c…
Capability Model	concept	Reference Models	A structured map of what a business does, independent of how it is organised or which systems support it, used to align technology investment with function.
Capacity Headroom	concept	Capacity Planning	The deliberate gap between current load and maximum capacity, sized to absorb growth, spikes and the loss of a failure domain.
Capacity Insurance Reliability Headroom, Standby Capacity	concept	Waste Elimination	Capacity that produces no value in normal operation and exists to make failures survivable - which looks identical to waste on a utilisation dashboard and must be defended explicitly.
Capacity Lead Time Provisioning Lead Time	concept	Capacity Modelling	The delay between deciding capacity is needed and having it available, which determines whether a capacity model can forecast at all or must instead buy optionality.
Cardinality	concept	Observability	The number of distinct time series produced by a metric, which is the product of the distinct values of all its labels — and the main driver of monitoring cost.
Cardinality Estimation	concept	Query Optimisation	The planner's prediction of how many rows each step of a query will produce — the input that determines every other choice it makes.
Cascading Timeout	concept	Timeouts & Deadlines	The effect of independently-chosen per-hop timeouts summing to a total far longer than any caller is willing to wait.
Cash-Releasing Benefit Hard Saving, Budget-Line Saving	concept	Business Cases	A benefit that reduces a named budget line on a known date, as distinct from released capacity or avoided cost - which are real but do not become money until a further decision is taken.
Causal Consistency	concept	Consistency Models	A model guaranteeing that operations which causally depend on one another are seen in the same order everywhere, while concurrent operations may be seen in any order.
CDC Initial Snapshot	concept	Change Data Capture	The consistent full copy taken when a CDC pipeline starts, before streaming begins — and the step that determines whether the target is correct.
Centralisation Trade-off	concept	Centralised vs Distributed	The exchange between consistency and control gained by centralising a capability and the autonomy and speed retained by distributing it.
Centralised versus Distributed	concept	Centralised vs Distributed	Whether a capability should be one shared thing or many independent ones — a recurring decision whose answer changes with organisation size.
Certificate Chain Chain of Trust	concept	TLS & Certificates	The sequence from a server's certificate through one or more intermediate CAs to a root the client already trusts.
Certification and Architecture	concept	Certification Impact on Architecture	How pursuing a certification shapes architecture — mainly through scope boundaries and the need for automatic evidence.
Certification Scope Boundary	concept	Certification Impact on Architecture	The declared set of systems, locations and people a certification covers, which determines both its cost and what it actually tells a customer.
Champion-Challenger Contamination Closed-Loop Evaluation Bias, Logged-Feedback Contamination	concept	Model Risk Management	The condition where a model's offline evaluation data was generated by the model it is being compared against, so the metric rewards imitation and improves while live outcomes stay flat.
Change Advisory versus Automated Gates	concept	Change Advisory vs Automated Gates	Whether change is controlled by human review or by automated verification — where the evidence favours automation and the regulation increasingly permits it.
Changelog Stream	concept	Stream-Table Duality	A stream whose records are keyed updates, so replaying it from the beginning reconstructs a table — the same information in the other of its two forms.
Choreography vs Orchestration	concept	Orchestration vs Choreography	Whether a multi-service process is driven by a central coordinator or emerges from services reacting to each other's events.
CI Secret Exposure Surface Build Credential Blast Radius, Runner Secret Surface	concept	Supply Chain Security	The set of credentials reachable by any code that executes in a build job, which is usually far larger than the job needs and is exposed in full by a single compromised step.
Circular Observability Dependency Blind Spot Cycle, Self-Observing Stack, Telemetry Co-Failure	concept	Failure Modes	When the tooling used to diagnose a failure runs on the infrastructure that is failing - so the outage removes the ability to see the outage, converting a technical problem into a search problem.
Client Request Waterfall Fetch Waterfall, Client-Side N Plus One	concept	API Shapes for UI	A chain of requests where each one can only start after the previous response arrives, so the screen's load time is set by the depth of the chain times the round trip rather than by bandwidth.
Client Runtime Constraint	concept	Frontend & Experience Architecture	The properties of the browser or device you do not control — CPU, network, version, extensions — which make the client a distributed system component rather than a rendering surface.
Clock Drift	concept	Physical-World Failure Modes	Device clocks diverging from real time, which corrupts ordering, expires certificates early or late, and produces data that appears to arrive from the past.
Clocks and Ordering Logical Clocks, Happens-Before	concept	Clocks & Ordering	Why wall-clock timestamps cannot order events across machines, and the mechanisms that can.
Cloud Databases	concept	Cloud Databases	Managed and cloud-native database services — where the operational relief is real, and where the abstraction leaks.