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

794 terms shown.

Term	Kind	Topic	What it is
Decision Rights Over Data	concept	Data Governance & Semantics	Who is entitled to decide what a data element means, who may see it and how long it is kept — the substance of governance once the policy documents are set aside.
Degradation Blindness Binary Health Thinking, Up-Or-Down Fallacy, Slow-Is-Not-Down	concept	Failure Thinking	Designing and monitoring for components that are either working or failed, when the dangerous and more common state is working slowly - which health checks report as healthy and retries make worse.
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.
Delivery versus Maintainability	concept	Delivery vs Maintainability	Shipping faster now by accepting future cost — a legitimate trade when it is deliberate, recorded and repaid.
Dependency Confusion Internal Package Name Hijack, Registry Resolution Confusion	concept	Supply Chain Security	A build resolving an internal package name from a public registry because the package manager prefers the highest version across all configured sources - an anti-pattern in resolution configuration rather than…
Dependency Inversion	concept	SOLID	The rule that high-level policy should not depend on low-level detail, both depending instead on an abstraction owned by the policy.
Dependency Rule	concept	Clean Architecture	The constraint that source-code dependencies may point only inward, from detail toward policy, regardless of the direction of control flow.
Deployment Order Coupling Upgrade Ordering Constraint, Schema Rollout Order	concept	Schema Registry	The constraint that a schema compatibility mode really expresses - which side of an interface must be upgraded first - rather than any statement about whether a change is safe.
Deployment Topology View	concept	Deployment Diagrams	A diagram showing where software actually runs — regions, zones, networks and hosts — which is where availability and cost properties become visible.
Derived Store Discipline One Authoritative Store Per Fact, No Dual Authority	concept	Polyglot Persistence	The rule that every fact has exactly one authoritative store and every other copy is explicitly derived, rebuildable and populated by a documented pipeline - the discipline that makes multiple datastores defensible.
Design Patterns	concept	Design Patterns	Named solutions to recurring design problems — valuable primarily as shared vocabulary, and harmful when applied as a goal.
Design System	concept	Design Systems	A versioned library of components, tokens and patterns that encodes an organisation's interface decisions as reusable code.
Device Identity	concept	Device Identity	Establishing and maintaining a trustworthy identity for each device in a fleet — including the parts that must work for a decade without physical access.
Device Telemetry at Scale	concept	Device Telemetry at Scale	The volume problem created by many devices each emitting small frequent messages, where the answer is filtering at the edge rather than ingesting everything.
Device-Side Refusal Local Precondition Check, The Device Decides	concept	OTA Updates	The rule that a device must refuse an unsafe instruction regardless of what the server commanded, because the server does not know the device's physical state.
Diagnostic Radius Failure Blast Radius, Signal Narrowness	concept	Test Pyramid Shapes	The number of distinct causes consistent with a test's failure - the property that actually separates the layers of a test suite and decides what a red build costs to investigate.
Diagram Altitude	concept	Architecture Diagrams	The level of abstraction a diagram commits to, and the rule that mixing levels in one picture makes it useless to every audience.
Diagram Maintenance Economics Which Diagrams to Keep, Stale Diagram Cost	concept	C4 Model	The rule that a diagram earns its maintenance cost only when it explains something hard to derive from source - which is why structure diagrams below the container level should be generated or absent.
Differencing Attack Query Differencing, Reconstruction Attack	concept	Data Sharing & Clean Rooms	Inferring an individual's data from the difference between two permitted aggregate results - the reason that returning only aggregates is not by itself a privacy guarantee.
Differential Privacy Budget	concept	Privacy-Enhancing Technologies	The cumulative privacy loss permitted across all queries against a dataset, which must be tracked and exhausted rather than applied per query.
Digital Sovereignty	concept	Digital Sovereignty	Requirements that data and the ability to operate on it remain under a jurisdiction's control — a stronger and more architecturally demanding constraint than residency.
Distributed Monolith	concept	Microservices	A system split into services that must still be deployed, changed and operated together, incurring distribution costs without independence.
Distributed Trace	concept	Distributed Tracing	A causally-linked record of one request's path across services, composed of spans that carry timing, attributes and parent relationships.
DNS Resolution Chain	concept	DNS	The sequence of lookups from browser cache through OS cache, recursive resolver, root, TLD and authoritative server that turns a name into an address.
DNS TTL	concept	DNS	The time a DNS record may be cached, and a value that resolvers, operating systems and applications honour inconsistently.
Documentation Decay	concept	Documentation Practice	The tendency of written documentation to become inaccurate faster than it is updated, making stale documentation actively more harmful than none.
Documentation Half-Life Doc Decay, Staleness Rate	concept	Architecture Documentation	The observation that architecture documentation decays in proportion to how much it restates current structure, and that the artefacts which survive are the ones that were always historical.
Domain Data Ownership	concept	Data Mesh	Making the team that generates data accountable for publishing it fit for others to use, rather than handing raw extracts to a central team.
Dual-Run Cost Overlap Migration Cost Hump, Parallel-Running Overlap	concept	Architecture Cost Modelling	The period in any platform migration when both the old and the new system are paid for at once, which raises the run rate before it falls and sets the true date on which a cost business case begins to pay back.
Durability vs Availability	concept	Cloud Storage	Two different storage guarantees — whether data survives, and whether it can be reached right now — routinely conflated because both are quoted in nines.
EA Domain Layers	concept	EA Domains	The four conventional layers of enterprise architecture — business, data, application and technology — each answering a different question about the estate.
EA Domains	concept	EA Domains	The four conventional views of an enterprise — business, data, application, technology — and what each is actually for.
EA Frameworks	concept	EA Frameworks	The available enterprise architecture frameworks, what each contributes, and the common failure of adopting one wholesale.
ECMP Flow Pinning Flow Hashing, Per-Flow Path Selection	concept	Network Performance	Because a router picks one of several equal-cost paths by hashing a flow's five-tuple, one connection is confined to one link, so aggregate capacity is never per-connection capacity.
Edge Capability Gradient Point-of-Presence Capability Ladder, Edge Tiering	concept	Edge Computing	The systematic decline in what a location can do as it moves closer to the user - thousands of points of presence with constrained runtimes and no writable store at one end, a few dozen full regions at the oth…
Edge Compute Topology	concept	Edge Compute Topologies	The choice of where computation sits along the path from device to region, trading latency and autonomy against manageability and consistency.
Edge Computing	concept	Edge Computing	Running computation at points of presence near users rather than in a central region, trading capability for round-trip latency.
Edge Data Consistency	concept	Edge Data Consistency	The consistency model available when data is replicated to many edge locations, where strong consistency would eliminate the latency benefit that motivated the edge.
Edge Function	concept	Edge Computing	Code executed at a CDN point of presence close to the user, in a constrained, fast-starting runtime, typically to modify or route a request before it reaches an origin.
Edge Security and Attestation	concept	Edge Security & Attestation	Establishing that a device is running expected software and has not been tampered with — the trust foundation when you do not control the physical environment.
Edge, Mobile and IoT	concept	Edge, Mobile & IoT	Architectures where compute sits on devices or near users — sharing the constraints of intermittent connectivity, limited resources and clients you cannot upgrade.
Efficient Concurrency Point Optimal Pool Size, Contention Threshold	concept	Connection Pooling	The concurrency level beyond which adding parallel work reduces total throughput, because contention costs more than the parallelism gains - and the reason a larger connection pool often makes latency worse.
Egress Cost Data Transfer Out	concept	Cost & FinOps	The charge for moving data out of a cloud provider or across its zones and regions — usually the least-anticipated line on a cloud bill.
Egress Pricing	concept	Cloud Pricing Models	The asymmetric charging model in which data entering a cloud is free and data leaving is billed, shaping architecture more than compute pricing does.
Elastic Cost Blindness Soft Constraint Failure, Invoice-Delayed Feedback	concept	Cost Governance	The failure mode of elastic platforms - the system satisfies any request rather than refusing it, so a capacity problem becomes a cost problem that reports itself a month late.
Embedding	concept	AI-Era Architecture	A dense numeric vector representing a piece of content, positioned so that semantically similar content sits nearby.
Embedding Table Collision Hashing Trick Collision, ID Bucket Collision	concept	Embeddings	Two unrelated identifiers mapped to the same row of a fixed-size embedding table, so their learned representations are averaged together and the model quietly treats distinct items as one.
Embeddings	concept	Embeddings	Dense numeric representations of content that place similar things close together — the substrate of semantic search and retrieval.
Emergent Failure Scale-Dependent Failure, Threshold Failure, Non-Linear Breakage	concept	Performance Test Design	A failure that exists only above a particular absolute scale because it depends on a fixed threshold rather than a ratio - which is why scaled-down environments validate code and not capacity.
Emergent Failure Interaction Failure, Composition Failure	concept	Systems Thinking	A failure produced by the interaction of components that are each behaving correctly - the class that component review cannot find and that dominates outages in mature systems.
Encapsulation	concept	Architecture Fundamentals	Keeping a component's state private, so it can only be changed through operations that maintain its invariants.
Encryption	concept	Encryption	Protecting data in transit, at rest and in use — where key management is the actual architecture and the cipher choice is the easy part.
End-to-End Test Cost Curve	concept	End-to-End Test Economics	How the cost of a broad end-to-end suite grows with its size while its marginal value falls, and where the two cross.
End-to-End Test Economics	concept	End-to-End Test Economics	The compounding maths that makes large end-to-end suites unaffordable and untrustworthy at scale.
Enterprise Integration	concept	Enterprise Integration	How applications across an estate exchange data — where the topology matters more than the technology and canonical models are the recurring trap.
Environment Ladder	concept	Environment Strategy	The ordered set of environments a change climbs, where each rung is justified by a distinct claim it can prove that the one below cannot.
Environment Parity	concept	Environment Parity	How closely a pre-production environment reproduces the properties of production that actually cause failures.
Ephemeral Port Exhaustion Source Port Starvation, TIME_WAIT Exhaustion	concept	Network Performance Tuning	The failure in which a host runs out of source ports for new connections to one destination, producing connection errors that look like the remote being down while the remote is healthy.
Erasure Amplification Deletion Write Multiplier, Purge Fan-Out	concept	Retention & Purge	The ratio between the bytes rewritten to honour a deletion request and the bytes actually belonging to the subject, which decides whether on-demand erasure is feasible or must be batched.