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
Cluster Architecture	practice	Cluster Architecture	How many clusters, how they are divided, and what shares fate — decisions about blast radius and operational burden rather than about capacity.
Cluster Multi-Tenancy Soft Multi-Tenancy, Namespace Tenancy	concept	Platform Tenancy	Multiple teams or workloads sharing one cluster, isolated by namespaces, quotas and policy rather than by separate infrastructure.
Cluster Split Axis	concept	Cluster Architecture	The dimension along which the estate is divided into clusters — the single decision that determines both blast radius and operational load.
Co-Change Analysis Change Coupling, Logical Coupling	practice	Service Boundaries	Using version-control history to find which components change together - the strongest available evidence that a proposed boundary is right or wrong.
Code List Governance	practice	Reference Data	Managing the small shared enumerations — currencies, country codes, statuses, product categories — whose uncontrolled change breaks systems quietly.
Code Review	practice	Code Review	Peer inspection before merge — valuable for knowledge sharing and design feedback, and reliably harmful when it becomes a latency bottleneck.
Coexistence Period	concept	Coexistence Patterns	The interval during which old and new systems both operate and must be kept consistent, which is longer, more expensive and riskier than most plans assume.
Cognitive Load	concept	Platform Team Topologies	The total amount a team must hold in mind to do its work, treated as a hard constraint on how much a team can own.
Cohesion	concept	Architecture Fundamentals	The degree to which everything inside one component belongs together and changes for the same reason.
Cohesion in Practice	concept	Cohesion	Whether the things inside a boundary belong together — measured by whether they change for the same reason and at the same time.
Cold Start at the Edge	concept	Edge Functions	The initialisation delay when a request reaches a location with no warm instance, which at the edge occurs far more often because traffic is spread across many locations.
Cold-Start Amortisation Warm Affinity, Startup Cost Reduction	practice	Serverless	Attacking the startup cost itself - through snapshots, lazy image pulls, local artefact caches and affinity routing - rather than choosing between scaling strategies that all suffer from it.
Collective Communication Cost Allreduce Overhead, Synchronisation Cost at Scale	concept	Throughput	The synchronisation term that determines how far a distributed training or inference job can scale, made of a bandwidth component that is nearly flat in participant count and a latency component that is not.
Command Validity Window Command Expiry, Time-Bounded Actuation	practice	Fleet Management	An expiry attached to a command sent to a device, so that an instruction delivered after the situation has changed is discarded rather than executed.
Command vs Notification Event Semantics, Obligation vs Fact	concept	Event-Driven Integration	Whether a published message requests an action someone is responsible for, or states a fact the publisher does not care who consumes - and why conflating them causes outages.
Commercial Literacy	concept	Business Understanding	Sufficient understanding of how the business makes money and what it is measured on to translate technical work into terms that compete for funding.
Commitment Coverage	metric	Reserved & Committed Capacity	The proportion of steady-state usage covered by discounted commitments, balanced against the risk of committing to capacity that is no longer needed.
Commitment Floor Minimum Spend Obligation, Contracted Spend Floor	concept	Reserved & Committed Capacity	The minimum spend a contract obliges you to pay regardless of usage, which makes efficiency gains unrealisable until the term ends and therefore sets the pace of cost programmes and migrations.
Commitment Read Never Commit From Cache, Authoritative at the Point of Action	concept	Client Caching & Data Layer	The rule that the read immediately preceding an irreversible action must come from the authoritative source, which is what allows everything else in the interface to be aggressively cached.
Common Coupling Shared Mutable State Coupling, Shared Database Coupling	concept	Coupling	Coupling through shared mutable state, where every participant constrains every other participant's ability to change - the one form of coupling with no natural upper bound.
Common-Cause Risk Shared Dependency Risk, Correlated Risk Cluster	concept	Risk Assessment Methods	Several separately scored risks that all fire on the same underlying event, so a register scoring them independently ranks one large loss as a set of medium ones and funds none of them.
Communicating a Threat Model	practice	Communicating Threat Models	Producing a threat model that engineers act on — structured by data flow, prioritised by risk, and expressed as work rather than as a report.
Communicating with Engineers	practice	Presenting to Engineers	Earning technical credibility and giving guidance that engineers act on — which depends more on how the reasoning is shared than on whether it is correct.
Communication Capture Obligation Off-Channel Risk, Supervised Communications	practice	Records Retention & Legal Hold	A duty to preserve and produce business communications, which fails whenever the compliant channel is less convenient than an available alternative - making channel design, not policy, the control that determi…
Compaction File Consolidation, OPTIMIZE, Small File Remediation	practice	File Formats & Compaction	Rewriting many small data files into fewer larger ones, with sorting, as a required background process - because streaming ingestion produces small files continuously and a table without compaction degrades si…
Compaction Lag Cleaner Lag, Dirty Segment Lag	concept	Stream-Table Duality	The delay between a key being overwritten and the superseded record actually being removed, which decides how much larger a compacted topic is than its key set and how long a rebuild from it takes.
Comparative Canary Control-Group Canary, A/B Rollout Analysis, Baseline Comparison	pattern	Progressive Delivery	Evaluating a canary against a simultaneously-running control group of the same size rather than against fixed thresholds, so environmental variation cancels out and genuine regressions are detectable at much s…
Compatibility Mode	concept	Schema Registry	The registry setting that defines which schema changes are permitted — backward, forward, full, or none — and therefore what upgrade order is safe.
Compatibility Window Overlap Window, Dual-Version Period	concept	Platform APIs	The period during which two versions of a caller or message must both work, set by deployment and queue mechanics rather than by how many consumers there are, which is why even a single internal consumer requi…
Compensating Control	practice	Stakeholder Analysis	A cheaper measure that reduces a risk enough to proceed, used deliberately and with an expiry, when the full control cannot be delivered in the available time.
Compensating Manual Control Load-Bearing Workaround, Downstream Correction, Shadow Correction Step	concept	Legacy Assessment	A human step outside a legacy system that corrects its output before anyone consumes it, which means the real specification is the code plus the correction - so a replacement validated against the code alone i…
Compensating Transaction	pattern	Sagas & Compensation	A business operation that semantically undoes a previously committed step — not a rollback, because the original effect was visible and may not be fully reversible.
Compensation Impossibility Irreversible Step, Uncompensatable Action	concept	Sagas & Compensation	The recognition that some saga steps have no true compensating action, and the design rule that follows - order steps by reversibility and gate the irreversible ones.
Competing Consumers	pattern	Competing Consumers	Multiple instances reading from the same queue, each taking different messages, so throughput scales by adding consumers.
Complementary User Entity Control CUEC, User Control Consideration	practice	Three Lines Model	A control the service provider's auditor assumed the customer operates, so that a clean vendor opinion only holds for customers who are actually running it.
Completeness Indicator As-Of Metadata, Result Confidence Marker	practice	Streaming SLOs	Metadata published alongside a streaming result stating how current it is and what proportion of expected input it reflects - so consumers can reason about staleness instead of assuming currency.
Completeness SLO Did Everything Arrive, Delivery Completeness	metric	Streaming SLOs	The proportion of produced events that actually reached the destination - the streaming SLO that is measured least often and whose absence conceals the most damaging failure.
Complexity Budget	concept	Reliability vs Complexity	The idea that an organisation can operate only a bounded amount of complexity, so each resilience mechanism must justify its share.
Compliance Framework SOC 2, ISO 27001, PCI DSS	practice	Security Architecture	A published set of control requirements an organisation is assessed against, which turns security posture into evidence somebody else will check.
Compliance Frameworks	concept	Compliance Frameworks	Externally defined control sets — SOC 2, ISO 27001, PCI DSS and others — whose architectural impact is scope, evidence and segmentation.
Compliance Obligation Mapping	practice	Regulatory Constraints	Translating regulatory text into specific, testable technical requirements attached to the systems they apply to.
Compliance Perimeter Scope, In-Scope Estate	concept	PCI-DSS Scoping	The set of systems subject to a compliance regime - whose size is the dominant cost of that regime, and which is determined by architectural decisions rather than by the assessment.
Compliance Scope Boundary Scope Reduction, Cardholder Data Environment	practice	PCI-DSS Scoping	The set of systems subject to a compliance regime - determined by where regulated data flows, and reducible by architecture rather than by adding controls.
Compliance Scope Reduction Scope Minimisation, Descoping	pattern	Certification Impact on Architecture	Designing so that regulated data never touches most of the estate, which removes systems from assessment entirely rather than adding controls to them.
Component Contracts	practice	Component Contracts	The interface a shared UI component presents — where the discipline is refusing options as much as providing them.
Component Library Versioning	practice	Design Systems	Treating a design system as a versioned product with a compatibility policy and a deprecation process, because its consumers cannot all upgrade at once.
Composed Page Budget Aggregate Performance Budget, Whole-Page Budget	practice	Micro-Frontends	A performance budget enforced on the assembled page rather than per independently-owned fragment - because in a composed frontend nobody owns the total that users experience.
Composition Accessibility Defect Assembled-Page Accessibility Defect, Integration-Level A11y Failure	concept	Accessibility Testing	An accessibility failure that exists only in the assembled page - focus order, landmark duplication, heading structure, announcement rate - and that every individually conformant component can pass its own che…
Computation-Only Collaboration	pattern	Data Sharing & Clean Rooms	Two parties analysing their combined data without either receiving the other's records, by permitting only queries whose outputs are aggregate.
Compute Isolation Boundary	concept	Data Platform Tenancy	The line across which one domain's analytical workload cannot affect another's performance, cost attribution or access.
Compute Models	concept	Compute Models	Virtual machines, containers, serverless functions and dedicated hardware — chosen by workload shape rather than by modernity.
Compute Optimisation	practice	Compute Optimisation	Reducing compute spend through sizing, scheduling, purchasing model and architecture — in increasing order of both effort and payoff.
Compute Tier Placement	concept	Edge Compute Topologies	Deciding which of on-device, on-premises, metro, regional or central compute a workload belongs to, from its latency, data volume and autonomy requirements.
Concentration Risk Systemic Dependency, Single-Provider Exposure, Vendor Concentration	concept	Third-Party Risk	The exposure created when many organisations, or many parts of one organisation, depend on the same provider - so that a single failure is correlated across the system rather than isolated.
Concern Restatement Tax Layer Tax, Shotgun Surgery	concept	Separation of Concerns	The fixed, permanent cost paid by every feature when architectural layers restate the same concern at several altitudes instead of separating different concerns.
Concurrency	concept	Concurrency	How many operations are in flight at once — the quantity that actually saturates a system, and the one most worth limiting explicitly.
Concurrency Limiting	pattern	Fault Isolation	Bounding the number of simultaneous in-flight operations so that overload produces fast rejection rather than resource exhaustion.
Configuration as Change Config-Code Parity, Data Deployment Rigour, Non-Code Change Control	concept	Change Management vs CD	Applying the review, validation, staging and rollback discipline of code deployment to configuration, content and data updates - because they change production behaviour, ship more often, and are interpreted w…
Configuration Corpus Parity Input Corpus Parity, Config Space Coverage	concept	Environment Parity	How closely the set of configurations a pre-production environment exercises resembles the set production actually carries - the parity dimension that decides whether a config-triggered latent bug is found by …
Configuration Drift	concept	IaC Modules & Drift	The gap that opens between the infrastructure your code describes and the infrastructure that actually exists.