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

75 terms shown.

Term	Kind	Topic	What it is
Aspirational and Achievable SLO	practice	SLI, SLO & SLA	The distinction between the reliability a team wishes for and the reliability its current architecture and dependencies can actually deliver.
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.
AWS: Static Stability Across Availability Zones Static Stability	case-study	Static Stability	AWS designs services to keep working with the capacity they already have when a zone fails, rather than needing the control plane to provision replacements.
Blameless Postmortem Learning Review, Incident Retrospective, Non-Attributive Analysis	practice	Postmortems	An incident analysis structured so that participants can disclose what actually happened without personal risk - which is a technical requirement for accurate information, not a cultural courtesy.
Blameless Postmortem	practice	Reliability & Resilience	An incident review that seeks the systemic conditions that made a failure possible, explicitly excluding individual fault.
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 Analysis	practice	Fault Isolation	Determining, for each component, exactly what fails and who is affected when it fails completely.
Blast Radius Staging Graduated Rollout, Progressive Shedding	practice	Failover	Applying a change or a traffic shift in increasing increments gated on health, so that a wrong decision affects a bounded population before it affects everyone.
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 Planning	practice	Reliability & Resilience	Deciding in advance how much capacity will be needed, given growth, seasonality and failure scenarios, and ensuring it can be there in time.
Chaos Engineering	practice	Reliability & Resilience	Deliberately injecting failure into a system to discover, before an incident does, which of your resilience assumptions are false.
Chaos Engineering in Practice	practice	Chaos Engineering	Deliberately injecting failure into production to verify that resilience mechanisms work — an experiment with a hypothesis, not vandalism.
Concurrency Limiting	pattern	Fault Isolation	Bounding the number of simultaneous in-flight operations so that overload produces fast rejection rather than resource exhaustion.
Contributing Factors Analysis	practice	Postmortems	Identifying the multiple conditions that combined to produce an incident, in place of searching for a single root cause.
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.
Dark Failover Shadow Failover, Non-Serving Failover Rehearsal	practice	DR Testing	Bringing a standby environment to full serving readiness and exercising it with synthetic or internal traffic while production continues untouched, so recovery is measured without an outage being risked.
Degradation Ladder Kill Switch List, Feature Shedding Order, Brownout Plan	practice	Degradation Modes	An ordered, pre-agreed list of features that can be disabled under stress, each with a switch that works without deployment, a named owner, a trigger condition and a rehearsed fallback.
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.
Disaster Recovery DR	practice	Reliability & Resilience	The plan and capability for restoring service after an event that takes out a whole site, region or system.
Durable Execution Workflow Persistence, Resumable Orchestration	pattern	Reliability & Resilience	Persisting a workflow's progress outside the process executing it, so that worker restarts, deployments and crashes resume from the last completed step rather than losing position.
Error Budget Reliability Budget, SLO Budget, Failure Allowance	practice	Error Budgets	The permitted amount of unreliability implied by an SLO, used as an automatic arbiter between shipping features and improving reliability - and, when unspent, as evidence that the system is more reliable than …
Error Budget	metric	Reliability & Resilience	The amount of unreliability an SLO permits, treated as a resource that feature velocity spends.
Error Budget Policy	practice	Error Budgets	The pre-agreed consequences of exhausting an error budget, which is what turns an SLO from a metric into a decision-making mechanism.
Failover	pattern	Failover	Switching to a standby when the primary fails — where detection, fencing and the decision to automate are harder than the switch itself.
Failover Orchestration	pattern	Failover	The sequence of detection, decision, promotion and traffic redirection that moves service from a failed component to a healthy one.
Failover Propagation Delay Client Convergence Time, Failover Tail	metric	Failover	The interval between a failover completing on the server side and the last client actually using the new location, which is usually the larger part of the recovery time users experience.
Failure Injection Testing	practice	Resilience Testing	Deliberately introducing faults into a system under test to verify that timeouts, retries, fallbacks and circuit breakers behave as designed.
Fallback Independence	practice	Graceful Degradation	The requirement that a degraded path fail independently of the primary - and be exercised continuously, because fallbacks that are never run do not work.
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.
Feature Criticality Tiering	practice	Graceful Degradation	Classifying product functionality by whether it must work, should work, or can be dropped, so degradation decisions are made in advance by the business.
Game Day	practice	Reliability & Resilience	A scheduled exercise in which a failure is deliberately introduced and the team responds as though it were real, to test the system and the response together.
Game Days	practice	Game Days	Scheduled exercises where a team responds to a simulated or injected failure, testing the humans and the process as much as the system.
Google SRE: Error Budgets as a Negotiation Device SRE Error Budget	case-study	Error Budgets	Google resolved the standing conflict between shipping speed and reliability by giving both sides a shared number and a pre-agreed consequence.
Graceful Degradation in Practice	pattern	Graceful Degradation	Deliberately reducing functionality to preserve the core when a dependency fails — a product decision expressed in architecture.
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.
Incident Command Incident Command System, ICS	practice	Reliability & Resilience	Assigning explicit roles during an incident — commander, operations lead, communications lead, scribe — so coordination does not compete with diagnosis.
Incident Severity Levels	practice	Incident Management	A small, agreed scale of incident severity that determines response, escalation and communication without requiring debate during the event.
Journey-Level SLO Per-Journey Availability, User-Facing SLI	practice	SLI, SLO & SLA	Setting reliability targets per user journey rather than per platform or per service, because consequence differs by journey and only a journey-level measurement reflects what a user experienced.
Load-Coupled Fault Injection Fault Injection Under Load, Contention Testing	practice	Chaos Engineering	Injecting dependency faults while the system is at realistic peak load, because timeouts, pool sizes and breaker thresholds only reveal whether they are correct under contention.
N+1 and 2N Redundancy	pattern	Redundancy	Provisioning one spare beyond required capacity versus provisioning double, and the failure assumptions each encodes.
Netflix: Chaos Monkey and the Simian Army Simian Army, Chaos Kong	case-study	Chaos Engineering	Netflix deliberately terminated production instances during business hours to force engineers to build for failure rather than hope against it.
Nines Table	concept	Availability Mathematics	The mapping between availability percentages and permitted downtime, and the cost curve that comes with it.
On-Call	practice	On-Call	The rotation that responds to production problems — a system whose health is measured by whether the people in it can sustain being in it.
Page Budget Pages Per Shift, Alert Budget	metric	On-Call	An explicit ceiling on how many pages a shift may generate, treated as a limit the team manages against rather than as an outcome it observes.
Postmortems Incident Review, Blameless Postmortem	practice	Postmortems	Structured learning from an incident, conducted so that the truth is obtainable — which requires that telling it is safe.
Pre-Provisioned Capacity	pattern	Static Stability	Running capacity that is already in place to absorb a failure, rather than depending on a control plane to create it during the failure.
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…
Recovery Point Objective RPO	metric	RTO & RPO	The maximum acceptable data loss measured as a duration, determining the replication and backup strategy.
Recovery Time Objective RTO	metric	RTO & RPO	The maximum acceptable duration between a failure and restored service, agreed with the business rather than chosen by engineering.
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.
Reliability Headroom	metric	Capacity Planning	The gap between provisioned capacity and the load that would be carried after the largest planned failure, measured under peak conditions.
Request-Based and Window-Based SLI	metric	SLI, SLO & SLA	Two ways of computing the same reliability target — counting good events, or counting good time windows — which produce materially different numbers.
Resilience Testing	practice	Resilience Testing	Verifying that failure-handling behaves as designed — a category of testing distinct from functional and load testing, and usually absent.
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.
Restore Verification	practice	DR Testing	Periodically performing a real restore from backup and validating the result, as the only evidence that a recovery capability exists.
RTO and RPO	metric	RTO & RPO	How long recovery may take, and how much data may be lost — the two numbers from which every disaster recovery design follows.