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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

2205 terms shown.

Term Kind Topic What it is
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.
Durable Execution Workflow-as-Code, Replay-Based Workflows, Persistent Execution pattern Saga Running workflow code whose complete execution history is persisted, so a crashed process resumes by replaying that history rather than restarting - which makes process failure an implementation detail rather …
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.
Dwell Time Mean Time to Detect metric Security Incident Response The period between an attacker gaining access and being detected — the metric that determines how much damage an intrusion can do.
Dynamic Secrets pattern Secrets Management Credentials generated on demand for a specific consumer with a short lease, rather than stored, shared and rotated periodically.
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 Framework Selection practice EA Frameworks Choosing how much formal enterprise architecture method an organisation needs, on the basis that most need considerably less than the frameworks describe.
EA Frameworks concept EA Frameworks The available enterprise architecture frameworks, what each contributes, and the common failure of adopting one wholesale.
EA Metrics metric EA Metrics Measuring whether an architecture practice is producing value — where output metrics mislead and outcome metrics are harder but real.
EA Value Metrics metric EA Metrics Measures that demonstrate what an enterprise architecture function has changed, chosen to avoid rewarding documentation volume.
eBay's Architectural Generations case-study Legacy Modernization eBay rewrote its core platform several times across its first decade, each time because the previous generation had hit a limit that could not be tuned away.
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 Aggregation pattern Device Telemetry at Scale Summarising or filtering telemetry at the device or gateway so that only what is needed leaves, which is usually the difference between a viable and an unaffordable design.
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 Functions tool Edge Functions Small units of code executed at points of presence near users — powerful for stateless work, constrained by the limits of the runtime and the difficulty of state.
Edge Personalisation pattern Edge Rendering Varying a cached response at the edge on a small number of attributes, so the page stays cacheable while still differing per visitor segment.
Edge Policy Ordering Gateway Filter Order, Admission Sequence practice API Gateway The sequence in which a gateway applies connection limits, authentication, quotas and validation, which decides whether a flood of unauthenticated traffic consumes your cheapest resource or your most expensive one.
Edge Rendering Edge-Side Rendering, POP Rendering pattern Edge Rendering Producing a page's HTML in a lightweight runtime at a CDN point of presence rather than in a regional data centre - which removes network distance from the response and adds distance to the data.
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 Triage On-Device Filtering, Selective Collection, Interesting-Event Upload pattern Fleet Management Deciding on the device which data is worth transmitting, because a fleet generates far more than any network can carry - and the common, uneventful case is also the least valuable.
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.
Effective-Dated Rules Temporal Rule Versioning, As-At Governance pattern Regulatory Constraints Storing business and regulatory rules as versioned configuration with effective dates, so a record remains governed by the rules that applied when it was created - without which every rule change requires a da…
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 Filtering practice Network Security Restricting what a workload may connect out to, which is the control that turns a compromise into a contained one.
Egress Path Analysis practice Network & Egress Costs Tracing where data physically moves in an architecture, because transfer charges follow paths that appear nowhere on the diagram.
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.
Egress-First Cost Modelling Bandwidth-Dominant Costing, Cost Order of Magnitude practice Cloud Architecture Establishing which cost category actually dominates before optimising anything - because in media-heavy consumer platforms the order is usually bandwidth, then storage, then compute, which is the inverse of wh…
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 Model Migration practice Embeddings The process of moving a corpus to a new embedding model, which requires re-embedding everything because vectors from different models are not comparable.
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.
Enabling Team pattern Platform Team Topologies A team whose output is other teams' increased capability, working alongside them temporarily rather than owning a component permanently.
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.
Encryption at Rest and in Transit practice Security Architecture Protecting stored data from disclosure if the medium is obtained, and network data from disclosure if the path is observed — two different controls against two different threats.
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 Architecture EA Practice, Architecture Function practice Enterprise Architecture The practice of owning the architectural decisions whose costs and benefits land on different teams or outside any team's planning horizon - the decisions competent delivery teams have no incentive or informat…
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.
Enterprise Integration Patterns EIP practice API & Integration A catalogue of named, composable messaging patterns — router, translator, aggregator, splitter, filter, dead letter channel — that gives integration work a shared vocabulary.
Entity Homing Home Region, Per-Entity Primary pattern Multi-Region Architecture Assigning each entity - customer, account, tenant - a single home region that owns its writes, so a regional outage affects a subset of entities rather than every write in the system.
Envelope Encryption pattern Key Management Encrypting data with a locally generated data key, then encrypting that key with a master key held in a key management service.
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.
Environment Strategy practice Environment Strategy The deliberate choice of how many pre-production environments exist, what each is for, and how faithfully each mirrors production.
Ephemeral Environment pattern Developer Environments A full environment created on demand for one change and destroyed afterwards, which removes the queue for shared environments and the drift within them.
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.
Equifax 2017: A Known Patch and an Expired Certificate Equifax Breach case-study Supply Chain Security An unpatched framework vulnerability provided entry, and an expired certificate on a monitoring device meant the exfiltration went undetected for months.
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.
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 …