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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
Contract Event Designed Event vs Row Change, Deliberate Emission concept Outbox An event a system deliberately emits with a schema it owns and a meaning it controls, as opposed to a captured row change that exposes the producer's table structure as a public interface.
Contract Testing Consumer-Driven Contracts practice Contract Testing Verifying that a provider satisfies what its consumers actually depend on, without deploying both together.
Contract Testing at Scale practice Contract Testing at Scale Operating consumer-driven contracts across hundreds of services, where the broker, versioning and deployment checks become the hard part.
Contract Verification Gate practice Contract Testing at Scale A provider's pipeline stage that replays every consumer's recorded expectations and fails the build if any would break.
Contributing Factors Analysis practice Postmortems Identifying the multiple conditions that combined to produce an incident, in place of searching for a single root cause.
Control Coverage Assurance Coverage, Estate Coverage concept Continuous Controls Monitoring The proportion of the actual estate a control operates on - the metric that determines whether monitoring provides assurance or false confidence.
Control Design vs Operating Effectiveness concept Control Design vs Operation The distinction between a control being correctly designed to address a risk and it actually having worked consistently over a period.
Control Plane and Data Plane concept Cloud Architecture The separation between the machinery that makes changes to a system and the machinery that serves its traffic.
Control Plane vs Data Plane concept Cloud Architecture The separation between the system that manages configuration and the system that serves requests, which have very different reliability requirements.
Control Test Automation practice Continuous Controls Monitoring Executing a control's test continuously against the whole population rather than sampling it annually, which changes both the detection latency and the strength of the evidence.
Control-Interval Matching Actuation Delay Matching, Feedback Loop Damping concept Failure Modes Setting a feedback loop's control interval to the delay of the thing it actuates - because a controller that adjusts faster than the system can respond amplifies noise instead of correcting error.
Control-Plane Amplification API Server Amplification, Fleet Agent Load Multiplication concept Platform Telemetry The property that a per-instance agent's load on a shared control plane scales with fleet size, so a change that is harmless in staging saturates the API server of the largest production cluster.
Control-Plane Push Amplification Config Fan-Out, xDS Amplification concept Service Mesh The property that one endpoint change can force a configuration push to every proxy in the fleet, making control-plane work scale with proxies multiplied by services rather than with either alone.
Convergence Without Coordination concept CRDTs The property that replicas applying the same set of updates in any order reach the same state, which is what removes the need for a central arbiter.
Conway's Law concept Architecture Fundamentals Systems tend to mirror the communication structure of the organisation that builds them.
Coordinated Omission Closed-Loop Measurement Bias, Omitted Latency Samples concept Load Testing The measurement error in which a load generator stops issuing requests while the system under test is stalled, so the slow samples that a real arrival process would have produced are never recorded.
Coordination Cost Change Coupling Cost, Cross-Team Latency, Lockstep Tax concept Conway's Law The delay and effort imposed on a change by the number of teams and services that must agree and release together - usually the dominant term in delivery lead time, and almost never instrumented.
Coordination Tax Cross-Team Feature Cost, Conway Misalignment Cost concept Conway's Law The permanent, structural cost incurred when service boundaries are drawn on a different axis from the way work arrives - and the reason consolidating services is sometimes an architectural improvement.
Coordination-Cost Metric Services Per Change, Teams Per Feature, Lockstep Ratio practice EA Metrics The number of independently-owned services and teams that must change together for a typical feature - the clearest available signal that architectural boundaries are imposing delivery cost, and one almost nob…
Core Web Vitals metric Core Web Vitals A small set of user-centred performance metrics covering loading, interactivity and visual stability, measured on real users rather than in a lab.
Correlated Degradation Demand-Coupled Failure, Peak-Correlated Dependency Risk concept Degradation Modes The condition where a dependency's reliability worsens for the same reason that user demand rises, so the system is least capable exactly when it is most needed.
Correlated Failure Common-Mode Failure, Shared Fate concept Redundancy Failures that are not independent, so redundancy multiplies far less than the arithmetic promises - usually because replicas share code, configuration or a deployment.
Correlated Region Failure Shared-Fate Region Dependency, Region Failure Correlation concept Single vs Multi-Region The shared dependencies that make two regions fail together, which is why multiplying regions multiplies cost but adds far less availability than independence arithmetic predicts.
Correlation ID practice Observability A single identifier attached to one logical operation and included in every log line it produces, anywhere in the system.
Correlation IDs Request ID, Trace ID pattern Correlation IDs A single identifier attached at the edge and carried through every hop, synchronous and asynchronous, that stitches an investigation together.
Cost Accountability Model practice Showback & Chargeback The arrangement determining whether teams merely see their costs or are financially charged for them, and the behaviour each produces.
Cost Allocation practice Cost Allocation Attributing spend to the team, service or customer that causes it — the prerequisite for every other cost conversation.
Cost Allocation Tagging practice Cost Allocation A mandatory, enforced tagging scheme that attributes every resource to an owner, so spend can be understood and acted on below the level of the whole account.
Cost Attribution Tagging Strategy, Cost Ownership practice Cost Allocation Assigning every unit of infrastructure spend to a team and a product, enforced at resource creation - the prerequisite without which no other cost control works.
Cost Driver Scaling Driver, Cost Dimension concept Architecture Cost Modelling The measurable quantity whose growth causes a cost to grow - identifying it correctly is what makes a cost model predictive rather than descriptive.
Cost Governance practice Cost Governance The guardrails, budgets and approval structures that prevent cost surprises without becoming a bottleneck.
Cost Model Sensitivity practice Architecture Cost Modelling Identifying which assumptions in a cost projection dominate the outcome, so effort goes into the estimates that actually matter.
Cost of Delay concept Portfolio Prioritisation The economic loss per unit of time that a decision or delivery is postponed, which turns prioritisation from opinion into arithmetic.
Cost of Downtime metric Cost vs Reliability The quantified business impact of unavailability per unit of time, which converts reliability investment from an argument into an arithmetic comparison.
Cost of Inaction Cost of Delay, Do-Nothing Cost practice Business Cases The quantified ongoing cost of leaving a system as it is - the number that lets architectural work compete against feature work for funding.
Cost per Request metric Cost per Request Total cost divided by units of business value — the metric that makes cost comparable across time, scale and design options.
Cost per Request metric Cost & FinOps The fully-loaded infrastructure cost of serving one request, and the unit that makes architectural cost decisions comparable.
Cost Per Transaction metric Performance vs Cost Infrastructure cost divided by business volume, which reveals efficiency trends that absolute spend conceals.
Cost Telemetry Lag Billing Data Delay, Spend Reporting Latency concept Cost Governance The delay between spend being incurred and appearing in billing data, which sets a floor on how fast any detective cost control can possibly react and explains why budget alerts arrive after the money is gone.
Cost versus Reliability concept Cost vs Reliability Reliability is bought with redundancy and headroom, both of which cost money — so the target must be chosen rather than assumed.
Cost vs Reliability Trade-off concept Cost & FinOps The non-linear relationship between availability and spend, which makes each additional nine roughly an order of magnitude more expensive.
Cost-Bearing Abstraction Budgeted Abstraction, Abstraction Over Finite Resources concept Abstraction & Encapsulation The principle that any abstraction which lets a caller express arbitrary intent over a shared finite resource must also expose a budget - otherwise the feature is a denial-of-service surface.
Cost-Weighted Rate Limiting Compute Units, Weighted Quotas pattern API Gateways Limiting callers by the resources their requests consume rather than by request count, because on any API where request cost varies by orders of magnitude, counting requests protects nothing.
Counter Reset Handling Monotonic Counter Semantics, Rate Reset Compensation concept Metrics The rule that a decrease in a cumulative counter is interpreted as a process restart rather than as negative work, which is what allows rates to survive deploys and what makes gauges-as-counters silently wrong.
Counter, Gauge and Histogram concept Metrics The three fundamental metric types, distinguished by what they represent over time and by which aggregations are valid.
Counterfactual Structure Test Driver Test, Would-The-Shape-Change Test practice Architectural Drivers The one-question test that separates architectural drivers from important features - remove this requirement, and would the structure of the system change?
Coupling concept Architecture Fundamentals The degree to which one component must know about, or change alongside, another.
Coupling in Practice concept Coupling The kinds of coupling that actually hurt, ranked by how much they constrain independent change.
Coverage Drift Shrinking Scope, Control Reach Decay concept Continuous Controls Monitoring A control operating perfectly on a diminishing share of the estate - passing every assessment of the systems it covers while providing progressively less assurance overall.
Covering Index Index-Only Scan concept Indexing An index that contains every column a query needs, so the query is answered from the index without reading the table at all.
CQRS Command Query Responsibility Segregation pattern CQRS Separating the model that accepts writes from the model that serves reads, so each can be optimised independently — at the cost of the gap between them.
CQRS Command Query Responsibility Segregation pattern Data Architecture Separating the model used to change state from the model used to read it, so each can be optimised independently.
CQRS as a Data Architecture pattern CQRS Treating the serving layer as a derived, rebuildable projection of an authoritative write store.
CRDT Conflict-Free Replicated Data Type concept CRDTs A data structure whose concurrent updates always merge to the same result regardless of order, removing the need for coordination or conflict resolution.
Credibility Budget Influence Capital, Spending Political Credit concept Influence Without Authority The finite standing an architect has to override or refuse, earned by being useful and by being right about things that mattered - and spent deliberately on the small number of decisions where inconsistency is…
Credit-Based Flow Control protocol Backpressure & Flow Control A scheme where a receiver grants the sender a budget of bytes or messages it may transmit, replenished as the receiver consumes.
Critical Path Analysis Span Critical Path, Blocking Time Analysis practice Distributed Tracing Identifying which spans in a trace actually block the response, as opposed to running in parallel, so optimisation effort targets the work that determines latency rather than the work that merely appears slow.
Cross-Border Transfer Mechanism SCCs, Adequacy Decision, Transfer Impact Assessment concept Cross-Border Transfer The legal basis required to move personal data from one jurisdiction to another, and the architectural evidence needed to support it.
Cross-Cutting Concern concept Separation of Concerns A responsibility that legitimately appears throughout a system rather than in one module, such as logging, authorisation, tracing or transaction management.
Cross-Functional Requirement concept Functional vs Non-Functional A quality the system must exhibit across its features rather than a behaviour it must perform, so named because it cuts across all functionality.