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

18 terms shown.

Term	Kind	Topic	What it is
Availability Arithmetic	concept	Availability Mathematics	Multiplying dependency availabilities in series and combining redundant components in parallel to derive a system's achievable availability.
Availability Calculation	concept	Reliability & Resilience	Deriving a system's availability from its components, remembering that dependencies in series multiply.
Availability Composition	concept	Availability Mathematics	How the availability of a system follows from its dependencies — multiplying for serial dependencies and improving sharply for redundant ones.
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.
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.
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.
Degradation Mode	concept	Degradation Modes	A defined, intentional reduced state of service that the system enters under specified conditions, with known behaviour and known exit criteria.
Degradation Modes	concept	Degradation Modes	Explicitly designed operating modes below "fully working" — declared, testable, and switchable rather than emergent.
Fault Domain	concept	Fault Isolation	A boundary within which a single failure is contained, defined by the infrastructure and dependencies that components inside it share.
Health Check Depth Shallow vs Deep Health Check, Dependency Health Check	concept	Failover	How much of a service's dependency graph a health check consults, which determines whether the check reports an independent fault or a shared one that every instance will report at the same moment.
Nines Table	concept	Availability Mathematics	The mapping between availability percentages and permitted downtime, and the cost curve that comes with it.
Recovery Cost Per Unit Remediation Cost, Recoverability, Time-to-Repair Per Node	concept	Fault Isolation	The effort required to restore one affected instance, device or tenant - the multiplier that decides whether a wide blast radius is an incident or a catastrophe, and the factor most often left out of risk asse…
Redundancy	concept	Redundancy	Multiple instances of a component so that one failing does not fail the system — valuable exactly to the extent the failures are uncorrelated.
Restore Granularity Recovery Unit, Restore Scope	concept	RTO & RPO	The smallest unit a recovery procedure can return without disturbing everything stored alongside it, which sets the real recovery time for any incident that affects a subset of the data.
Service Level Agreement SLA	concept	Reliability & Resilience	A contractual commitment about service level, with a defined remedy — usually a service credit — when it is missed.
Static Stability Stability Under Failure	concept	Static Stability	A system that keeps working correctly in its current state when its control plane or dependencies become unavailable, rather than needing them to stay running.
Toil	concept	Reliability Culture	Manual, repetitive, automatable operational work that scales linearly with the size of the service and produces no lasting improvement.