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

13 terms shown.

Term	Kind	Topic	What it is
Error Budget	metric	Reliability & Resilience	The amount of unreliability an SLO permits, treated as a resource that feature velocity spends.
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.
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.
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.
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.
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.
RTO and RPO Recovery Time Objective, Recovery Point Objective	metric	Reliability & Resilience	How long recovery may take (RTO) and how much data may be lost (RPO), the two numbers that determine the cost of a resilience design.
Service Level Indicator SLI	metric	Reliability & Resilience	The actual measurement of a service's behaviour that an objective is set against — a ratio of good events to valid events.
Service Level Objective SLO	metric	Reliability & Resilience	An internal target for a service level indicator, set below the level at which users notice, and used to decide whether to ship or to stabilise.
SLI, SLO and SLA	metric	SLI, SLO & SLA	The measurement, the internal target, and the external contract — with the error budget as the mechanism that makes the target consequential.
Time to Detect MTTD	metric	Incident Management	The interval between a problem beginning and someone knowing about it, which is often the largest and most reducible component of total incident duration.