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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
Invariant Containment Boundary Follows the Invariant, Transaction Test concept Service Boundaries The rule that a service boundary must contain any invariant that must hold exactly - so discovering that a split would break a transaction is evidence the boundary is wrong, not merely an obstacle.
Invariant-Aligned Partitioning Partition by Invariant, Single-Writer Per Entity concept Consistency Models Choosing the partition key so that every strong-consistency invariant falls entirely inside one partition - which converts distributed coordination into local serialisation.
Inverse Conway Manoeuvre practice Conway's Law Deliberately reorganising teams so that the architecture you want becomes the architecture the organisation naturally produces.
Inverted Capability Map System-Derived Capability Model, Inventory-Shaped Capability Map concept Capability Mapping A capability map whose boundaries and names were derived from the existing system inventory, so it confirms the current implementation and cannot show that the business needs something it is not organised to do.
Invisible Resource Exhaustion Silent Limit, Unattributed Failure concept NAT & Egress A class of failure where a shared finite resource outside the application's view is exhausted, producing intermittent unexplained errors while every local metric looks healthy.
IoT Ingest Architecture pattern IoT Ingest Architecture Receiving high-volume telemetry from a large device fleet — where connection count, backpressure and reconnection storms dominate the design.
Irreversible Operation Guard Soft Delete Window, Two-Person Destructive Control pattern Segregation of Duties The set of design choices that make a destructive action recoverable by default - a delay before permanence, a type check on the target, and a second approver for bulk effects.
Islands Architecture Partial Hydration, Selective Interactivity, Component Islands pattern Hydration Cost Rendering a page as static HTML with independently-hydrated interactive regions, so JavaScript is shipped and executed only for the parts that need it rather than for the whole page.
Jitter concept Retries & Backoff Randomising retry delays so that clients that failed together do not retry together.
Join Replay Misalignment One-Sided Replay, Split-Watermark Join concept Streaming Joins The failure that follows from replaying one input of a stateful join while the other stays live - event times no longer overlap, window state is never cleaned, and the output is wrong in both directions with n…
Join Strategies concept Query Optimisation The three ways a database combines two row sets — nested loop, hash join and merge join — and the conditions under which each is correct.
Journey-Level SLO Per-Journey Availability, User-Facing SLI practice SLI, SLO & SLA Setting reliability targets per user journey rather than per platform or per service, because consequence differs by journey and only a journey-level measurement reflects what a user experienced.
JSON Web Token JWT protocol Security Architecture A signed, self-contained token carrying claims, which a service can validate locally without calling the issuer.
Just-in-Time Data Access Time-Boxed Data Grant, Expiring Analytical Access pattern Data Access Models Replacing permanent read grants with short-lived grants issued on request with a recorded purpose, so that entitlement decays by default instead of accumulating for as long as someone stays employed.
JWKS JSON Web Key Set protocol Tokens & JWTs A published endpoint listing an issuer's current public keys, allowing resource servers to validate token signatures without a shared secret and to survive key rotation.
Kappa Architecture pattern Kappa vs Lambda Treating the stream as the single processing path, and handling historical reprocessing by replaying the log through the same code.
Keep-Lit Capacity Floor Keep-the-Lights-On Floor, Legacy Demand Floor, Maintenance Floor concept Rebuild vs Re-architect The share of engineering capacity a legacy system consumes no matter what else is planned, which decides whether a rebuild is funded at all - and which a change freeze defers rather than removes.
Keeping-the-Lights-On Baseline Run Reservation, KTLO Allocation practice Portfolio Prioritisation The share of engineering capacity that unplanned and maintenance work consumes whether or not it is planned, reserved explicitly so that roadmap commitments are achievable and the trade-off is visible.
Key Rotation practice Key Management Periodically replacing a cryptographic key with a new one while retaining the old for decrypting existing data, so exposure from any single key is bounded.
Key Skew concept Partition Keys & Ordering An uneven distribution of records across partitions, which caps throughput at the busiest partition regardless of how many exist.
Key-Custodian Separation Token Vault Separation, Split-Custody Pseudonymisation pattern Pseudonymisation Keeping the mapping or key that re-identifies pseudonymised data in a system with a different access path from the data itself - so a breach of the analytical store yields behaviour without people.
Keyed State Size metric Stateful Stream Processing The total state a job holds per key across all keys, which governs memory, checkpoint duration and recovery time.
Knight Capital: $440 Million in 45 Minutes Knight Capital Incident case-study Feature Flags A deployment that reached seven of eight servers, combined with a reused feature flag, activated dormant test code and destroyed the company in three quarters of an hour.
Knowledge Deprecation Deliberate Unlearning, Skill Retirement practice Continuous Learning Deliberately retiring expertise that has stopped predicting behaviour, keeping the invariants it taught and dropping the product surface, so a fixed learning budget is not consumed by maintaining currency nobo…
KPI Attribution Chain Benefit Attribution Chain, Metric Causal Chain practice Business KPIs The explicit path from an architecture change through an operational metric and a short-lag product metric to the business measure finance reports - with the lag and the counterfactual named - so the benefit c…
Kubernetes K8s tool Cloud Architecture A container orchestrator that continuously reconciles the running state of a cluster towards a declared desired state.
Kubernetes Operator pattern Kubernetes A custom controller that encodes operational knowledge for a specific application, reconciling a custom resource towards a desired state the same way built-in controllers do.
Kubernetes Resource Requests and Limits concept Kubernetes The declared minimum a container is guaranteed and the maximum it may consume, which drive scheduling, eviction and throttling in ways that are easy to get wrong.
KV Cache Attention Cache, Key-Value Cache, Prefix Cache concept LLM Application Architecture The per-session key and value tensors a transformer must hold in GPU memory to generate each subsequent token - the resource that limits concurrent sessions, and whose reuse across turns is the difference betw…
Label Inheritance Classification Propagation, Sensitivity Inheritance practice Sensitivity Labelling Automatically assigning a derived dataset the highest sensitivity of its inputs, so that aggregates and transformations do not silently escape the controls that applied to their sources.
Lakehouse pattern Data Lakes & Lakehouses Open table formats over object storage that add transactions, schema enforcement and incremental updates to a data lake.
Lakehouse concept Warehouse, Lake & Lakehouse An architecture combining a lake's cheap open storage with a warehouse's transactions, schema enforcement and query performance, through a table format layer.
Lakehouse Table Format tool Open Table Formats A metadata layer over object storage that adds atomic commits, snapshots and schema evolution to files that otherwise have none.
Lambda Architecture Batch and Speed Layer, Dual-Path Analytics pattern Kappa vs Lambda Running the same computation as both a scheduled recomputation over all retained history and a streaming job over recent events, so that any defect in the fast path is erased by the next full recomputation.
Landing Zone pattern Landing Zones The pre-built, policy-governed cloud foundation into which workloads are deployed — account structure, networking, identity, logging and guardrails.
Last Responsible Moment practice Evolutionary Architecture Defer an irreversible decision until the cost of deferring exceeds the cost of deciding - and define in advance the signal that says the moment has arrived.
Last Safe Start Date Programme Latest Start, Deadline Backstop Date metric Negotiation The externally imposed deadline minus the programme's duration and contingency - the date an architect computes and owns, which competes for funding in a way the distant vendor deadline does not.
Last Writer Wins pattern Sync & Conflict Resolution Resolving a conflict by keeping the version with the later timestamp — simple, deterministic, and it silently discards the other change.
Late-Data Policy Lateness Handling, Allowed Lateness practice Watermarks & Late Data The explicit decision about what happens to an event that arrives after its window has closed - drop it, route it aside, or update the emitted result.
Latency metric Latency How long one operation takes — a distribution, never a number, and dominated by its tail in any system with fan-out.
Latency Budget Decomposition practice Latency Allocating a total response-time target across the components of a request path, so each layer has an explicit share and overruns are attributable.
Latency Revenue Elasticity metric Performance vs Cost The measured change in a business outcome per unit of added or removed latency, which turns "faster is better" into an amount of money and tells you when to stop buying milliseconds.
Lateral Movement concept Zero Trust An attacker's progression from an initial foothold to more valuable systems, which is what turns a minor compromise into a breach.
Layer 4 vs Layer 7 Load Balancing concept Networking Balancing on connection metadata (IP and port) versus on the content of the request (path, host, headers).
Layer Contract Guarantee Not Position, Medallion Discipline concept Medallion Architecture The rule that a data layer is defined by the guarantee it makes to consumers, not by its position in a naming convention - without which the layers convey nothing.
Layer Enforcement Ratchet Violation Baseline, Architecture Debt Ratchet, Boundary Gate with Baseline practice Layered Architecture Gating a layering rule on a recorded baseline of existing violations that may shrink but never grow, so an architectural boundary becomes mechanical on a legacy codebase without a cleanup project first.
Layered Architecture N-Tier pattern Layered Architecture Organising a system into horizontal layers with a strict dependency direction — the default structure, valuable for its constraint rather than its shape.
Layered Architecture N-Tier pattern Architecture Patterns Organising code into horizontal layers — presentation, application, domain, data — where each layer may only call the one beneath it.
Layout Space Reservation Shift Prevention, Dimension Reservation practice Core Web Vitals Allocating space for content before it arrives, so that late-loading elements fill a gap rather than displacing what the user is already reading.
Lead Time for Changes metric Flow Metrics The elapsed time from code committed to code running in production.
Lead Time to Value metric Time to Market The elapsed time from identifying an opportunity to delivering measurable benefit, which is usually dominated by waiting rather than by building.
Leader Election pattern Distributed Systems The process by which a group of nodes agrees which one of them is currently in charge of a task that must not run twice.
Leader Election in Practice Coordinator Election, Primary Election pattern Leader Election Selecting one node to coordinate, why majority quorum is non-negotiable, and why fencing at the resource is what actually prevents corruption.
Leading and Lagging Indicator concept Business KPIs The distinction between a measure that predicts an outcome and one that confirms it after the fact, determining whether a metric can be acted on.
Leading Health Signal In-Band Invariant Signal, Detection-Latency Gate concept Deployment Strategies A rollout gate input whose latency is shorter than the damage it indicates - the property that decides whether any bake time can catch a defect, as distinct from how much traffic the rollout exposes.
Leaky Abstraction concept Abstraction & Encapsulation An abstraction whose underlying implementation details become visible or consequential, requiring users to understand what it was meant to hide.
Leaky Abstraction Cost concept Abstraction Level Choice What a consumer pays when a platform abstraction hides a mechanism they must nonetheless understand to diagnose or tune it.
Learning Debt concept Continuous Learning The accumulating gap between an architect's knowledge and the current state of the field, which compounds silently because nothing forces its repayment.
Lease concept Distributed Locking A lock with an expiry, granting exclusive rights for a bounded time so that a crashed holder cannot block the system forever.
Least Privilege concept Security Architecture Granting each identity only the permissions it needs, for only as long as it needs them.