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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
Dataset Deprecation Policy Dataset Sunset Policy, Retirement Notice Period practice Data Products The written rule stating how a published dataset or column is retired - the notice period, how consumers are identified, and what happens if they do not move - without which nothing can ever be removed.
Dataset Ownership Boundary Data Product Boundary, Published Dataset Surface practice Data Platform Architecture The line between a producing team's internal data and the surface it publishes - which is what makes decentralised data ownership safe rather than fragmenting.
Dead Letter Queue DLQ, Poison Message Queue pattern Dead Letter Handling A separate destination for messages that cannot be processed successfully, so one bad message does not halt the stream behind it.
Dead-Letter Budget Diversion Budget, Poison Rate Budget metric Dead Letter Handling A declared ceiling on the share and the age of records a pipeline may divert before it counts as failing rather than coping - with an owner and a defined action attached to each breach.
Deadline Exceeded concept Timeouts & Deadlines The error returned when a request's overall budget expires — semantically distinct from a per-hop timeout, and a signal that must not be retried blindly.
Deadline Propagation Budget Propagation, Request Deadline, Remaining-Time Passing pattern Timeouts & Deadlines Carrying the originating request's absolute deadline through every downstream hop so that each service works with the remaining budget - and refuses work that cannot finish in time, rather than starting it.
Deadline Propagation Deadline Budget, Request Deadline pattern Timeouts & Deadlines Passing the remaining time budget down each call in a request chain so downstream services never work on a request whose caller has already given up.
Deadline-Derived Queue Depth Deadline-Bounded Queue concept Concurrency The rule that a request queue's maximum depth comes from the client's deadline and the service's completion rate, so the queue can never hold work that will expire before it is served.
Debt Interest Rate Cost Per Unit Time, Debt Triage Axis concept Technical Debt How much a piece of technical debt costs per unit time in slowed delivery, incidents and effort - which, paired with the cost to fix, is what separates debt worth paying down from debt that merely looks unpleasant.
Debt Register practice Technical Debt A maintained record of known technical compromises with their cost, impact and repayment trigger, making debt manageable rather than merely felt.
Debugging Distributed Systems practice Debugging Distributed Systems A method for diagnosing failures whose cause is in a different service from the symptom.
Decision Context Capture practice Architecture Decision Records Recording the situation, constraints and forces that made a decision reasonable, so that later readers can judge whether it still applies.
Decision Debt Unrecorded Decision Backlog, Undocumented Choice Accumulation concept Decision Practice The accumulated set of choices a system embodies but nobody wrote down, which turns every later change into an archaeology exercise and makes safe modification depend on individual memory.
Decision Feedback Delay Judgement Lag, Architectural Feedback Latency concept Career Development The 12 to 36 months between making an architectural decision and observing its consequences, which is long enough that the loop stays open unless the record itself carries the falsifying signal.
Decision Granularity One Decision Per Record, Record Scope practice Architecture Decision Records How much a single decision record covers, chosen so a later change can replace exactly the part that has become wrong instead of invalidating a document that is mostly still correct.
Decision Half-Life metric Architecture Decision Records The observed time it takes for half a set of architecture decision records to be superseded, read as a diagnosis of how the records are written rather than of how unstable the system is.
Decision Latency Time to Architectural Decision, Decision Queue Time metric Organisational Constraints The elapsed time from a design question being raised to a decision being made, whose length changes not only when designs ship but how complicated they are - because optionality is the rational hedge against s…
Decision Narrative practice Writing Decision Records Writing a decision record so that the reasoning survives the author, focusing on the forces and the rejected options rather than the conclusion.
Decision Restatement Implementer Read-Back, Assent by Restatement practice Presenting to Engineers Requiring the people who will implement a decision to write back what they will build and why, so that agreement is demonstrated by the receiver rather than inferred from an approval click.
Decision Rights Decision Ownership, Accountable Decider practice Architecture Decision-Making An explicit statement of who decides what, so that consultation is bounded and decisions do not wait for a consensus nobody required.
Decision Rights Boundary Decision Scope Line, Local Versus Enterprise Decision concept EA Domains The line separating choices a team may make alone from choices that bind other teams - drawn by where the consequence of a mistake lands, not by the cost, size or difficulty of the decision.
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.
Decision Trigger Revisit Condition, Pre-Agreed Threshold practice Managed vs Self-Managed A number or condition agreed in advance that would cause a decision to be revisited - which converts a permanent choice into a monitored one and prevents both premature change and indefinite drift.
Decision Under Uncertainty practice Deciding Under Uncertainty Choosing when the information needed to be confident is unavailable, using the cost of being wrong rather than waiting for certainty.
Decision-Forcing Proposal practice Technical Proposals A written proposal structured so that deferring is visibly a choice with a cost, rather than a free default.
Decision-Making Under Uncertainty practice Meta-Skills Choosing well when the information is incomplete — by bounding the downside and buying information, rather than by waiting for certainty.
Decommissioning practice Decommissioning Actually switching off and removing a replaced system, which is where the savings in every modernisation business case live.
Decommissioning Discipline practice Decommissioning The work of actually switching a legacy system off, which is where migration savings are realised and which is routinely left undone.
Decomposition by Capability practice Application Decomposition Breaking a monolithic system into parts along business capability lines rather than technical layers, so that each part changes for one reason.
Deemed Status Provisional Outcome, Presumed Result, Timeout Resolution Rule pattern Financial Services Regulation A provisional outcome assigned to a transaction whose true result is unknown after a timeout, resolved later by reconciliation - because a payments rail cannot leave money in an indeterminate state indefinitely.
Default Deny practice Firewalls & Security Groups A firewall posture in which nothing is permitted unless explicitly allowed, as opposed to blocking known-bad traffic.
Definition of Done practice Quality Gates The agreed, explicit conditions under which work is finished, which functions as a quality gate only when it is automated and non-negotiable.
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 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 Ladder practice Architecture Roles A pre-agreed ordered list of capabilities the system sheds under load, with the ordering owned by the business and the mechanism owned by the architect.
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.
Deletion Horizon Erasure Horizon, Last-Copy Latency metric Data Subject Rights The elapsed time after an erasure request until the last copy of the record is gone or unreadable, set by the longest-lived derived copy rather than by the live database.
Deletion Propagation Purge Fanout, Erasure Propagation pattern Retention & Purge The mechanism that carries a deletion from the primary store to every derived copy - which is where retention and erasure obligations are actually met or missed.
Deletion Safety Threshold Mass-Delete Guard, Sync Blast Radius Limit practice Partner & B2B Integration A refusal to process a deletion batch above some proportion of the population without human confirmation - the control whose absence produces the most damaging incidents in synchronisation systems.
Deletion Verification practice Retention & Purge Proving that a deletion actually removed the data everywhere it existed, which is a harder problem than issuing the delete.
Deliberate Technical Debt practice Delivery vs Maintainability A consciously chosen shortcut, recorded with its cost and a repayment trigger, as distinct from debt incurred by carelessness.
Delivery Attempt Log Webhook Delivery History practice Webhooks A customer-visible record of every outbound delivery attempt - its response, timing and payload - which converts a support burden into self-service.
Delivery Pipelines practice Delivery & Release Engineering The automated path from commit to production — where speed and trustworthiness determine whether anyone uses the feedback it produces.
Delivery versus Maintainability concept Delivery vs Maintainability Shipping faster now by accepting future cost — a legitimate trade when it is deliberate, recorded and repaid.
Demand Forecasting practice Capacity Modelling Projecting future load from historical trends, business plans and known events, and translating it into resource requirements with explicit lead times.
Denormalisation practice Data Architecture Deliberately duplicating data across records to make reads cheap, accepting the write-time cost of keeping copies in step.
Denormalised Log Resolved-Asset Topic, Fat Event Stream pattern Kappa vs Lambda A second topic that republishes each record with its referenced data already resolved, so consumers read complete payloads instead of each performing the same joins against the normalised source of truth.
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 Reproducibility Same Commit Same Dependencies, Pinned Builds practice Build Reproducibility Guaranteeing that a given commit pulls the same dependencies every time - the practical subset of build reproducibility that delivers most of its value for a fraction of the effort.
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.
Deployability Test Can You Deploy Alone, Boundary Justification Test practice Microservices Asking whether one team can change, deploy and roll back a service without telling the others - the single test that distinguishes a boundary delivering independence from one delivering only cost.
Deployed-Artefact Assertion Fleet Version Assertion, Release State Check practice Testing in Production A check run after every deployment that compares the build identifier reported by each running host against the intended release, so a partially applied deployment fails loudly instead of running two behaviour…
Deployment Compatibility Check Can-I-Deploy, Deployment Gate on Contracts practice Contract Testing at Scale A pre-deployment query asking whether this version is compatible with everything currently deployed - which turns contract tests from a test into a release gate.
Deployment Diagrams practice Deployment Diagrams Where software actually runs — regions, zones, clusters, networks — and therefore what fails together.
Deployment Freeze Change Freeze, Code Freeze practice Change Management vs CD A period during which deployments are prohibited, intended to protect a high-stakes business window.
Deployment Gate Quality Gate, Approval Gate practice Deployment Gates A condition a change must satisfy before it advances, whether evaluated by a machine or signed by a person.
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 Pipeline CD Pipeline, Build Pipeline pattern Pipeline Architecture The automated path a commit travels from source to production, where every stage is a chance to reject the change and no stage can be skipped.