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
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.
Runbook Quality	practice	Incident Management	The properties that make an operational procedure usable by a tired responder under pressure, as opposed to a document that merely exists.
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.
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.
Severity Levels SEV Levels	practice	Reliability & Resilience	A predefined scale of incident impact that determines who is woken, how fast, and what process applies.
Shared-Cause Analysis What Is Shared, Redundancy Audit	practice	Redundancy	Auditing a redundant design by asking what every replica has in common, because redundancy protects against independent failure and not against anything shared by all copies.
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.
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.
Sustainable On-Call	practice	On-Call	An on-call arrangement whose alert volume, rotation size and compensation allow it to continue indefinitely without degrading the people in it.
Tabletop Exercise	practice	Game Days	A discussion-based walkthrough of a hypothetical incident that tests procedures and decision-making without touching any system.
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.
Toil	concept	Reliability Culture	Manual, repetitive, automatable operational work that scales linearly with the size of the service and produces no lasting improvement.
User Journey SLO Critical User Journey, CUJ	practice	SLI, SLO & SLA	Defining reliability targets around what a user is trying to accomplish, measured where the user is, rather than around per-request success rates at the server.
Value-Graduated Fallback Tiered Degradation by Stake, Risk-Weighted Fallback	pattern	Graceful Degradation	A degradation ladder whose depth depends on the value at stake, so a low-value transaction proceeds on weak signals while a high-value one fails closed - replacing a single binary decision that is always wrong…