Terminology
2225 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 areas2225
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 Architecture74
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 Architecture69
Streaming & Real-Time Data69
Data Governance & Semantics74
Frontend & Experience Architecture66
Edge, Mobile & IoT68
Regulatory & Data Protection Architecture65
Assurance, Audit & Model Risk69
74 terms shown.
| Term | Kind | Topic | What it is |
|---|---|---|---|
| Agent Handoff | pattern | Multi-Agent Systems | The transfer of a task and its context from one specialised agent to another, and the point at which multi-agent systems most often lose information. |
| Agent Loop | concept | Agent Architectures | The cycle in which a model observes state, selects an action, executes a tool and observes the result, repeating until a goal or a limit is reached. |
| Agent Tool Authorisation | pattern | Tool Calling | Enforcing that a tool invoked by a model executes with the requesting user's permissions rather than the application's, and that consequential actions require confirmation. |
| Agent Transcript Compaction Loop History Summarisation, Working Memory Compaction | pattern | Agent Architectures | Replacing the resolved middle of a long agent loop with a short summary while preserving the original goal and constraints verbatim, so token cost stops growing quadratically and late steps still follow early … |
| AI Gateway | pattern | AI-Era Architecture | A shared proxy in front of model providers that centralises routing, keys, quotas, caching, logging and safety policy. |
| AI Gateway Pattern LLM Proxy, Model Router | pattern | AI Gateways | A single control point through which all model calls pass, providing routing, cost control, caching, logging, guardrails and provider abstraction. |
| Approximate Nearest Neighbour Index ANN | concept | Vector Databases | An index that trades exactness for speed when finding similar vectors, making large-scale semantic search feasible. |
| Automation Ratchet Residual Difficulty, Hard-Case Concentration | concept | Human in the Loop | The effect where improving automation makes the cases reaching humans systematically harder, so reviewer throughput falls and error rates rise even as the overall system improves. |
| Candidate Recall Ceiling First-Stage Recall, Retrieval Ceiling | metric | Reranking | The share of queries whose correct passage appears anywhere in the first-stage candidate set - the hard upper bound on every later stage, since reranking reorders what was retrieved and cannot add to it. |
| Capability Confinement Least-Privilege Agents, Trust Domain Separation, Action Authorisation | concept | Prompt Injection Defence | Limiting what an agent is authorised to do rather than trying to prevent it from being misled - because a model cannot reliably distinguish instructions from data, so the security boundary must sit outside it. |
| Chunk Boundary Strategy | practice | Chunking & Retrieval | How source documents are split for embedding, which determines whether retrieved passages are self-contained and coherent. |
| Chunked Prefill Prefill Splitting, Interleaved Prefill, Piecewise Prompt Processing | pattern | AI Cost Management | Breaking a long prompt's prefill into pieces interleaved with other sequences' decode steps, so that one enormous request cannot stall every in-flight interactive response. |
| Context Window | concept | AI-Era Architecture | The maximum number of tokens a model can attend to in one request, holding the system prompt, history, retrieved context, tools and the answer. |
| Context Window Budget | concept | LLM Application Architecture | The finite token allowance per request, treated as an engineering resource to be allocated deliberately between system instructions, retrieved context, history and output. |
| Contextual Retrieval Contextual Chunk Prefixing, Contextual Embeddings | pattern | Chunking & Retrieval | Prepending a short generated description of where a chunk sits in its document before embedding it, so that a passage full of pronouns and bare figures still matches the query that should find it. |
| 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. |
| Escalation Threshold | practice | Human in the Loop | The rule determining when a model's output is acted on automatically and when it is routed to a person. |
| Evaluation Set Contamination Benchmark Leakage, Golden Set Overfit | concept | LLM Evaluation | The gradual loss of an evaluation set's ability to predict production quality as its cases leak into training data, into prompts, or into months of iteration against the same examples. |
| Feature Store | tool | ML Platform | A system that computes, stores and serves model input features consistently for both training and inference, eliminating training-serving skew. |
| Filtered Vector Search Predicate-Constrained ANN, Metadata Filtering in ANN | pattern | Vector Databases | Combining a metadata predicate with approximate nearest-neighbour search - where the predicate's selectivity, not the corpus size, decides whether results are correct or latency collapses. |
| Guardrail Availability Policy Fail-Open Guardrail Decision, Safety Check Degradation Policy | practice | Guardrails | The decision, made in advance and per action class, about what the system does when a safety check cannot run - because the alternative is that a timeout in a classifier decides your safety posture at 03:00. |
| Guardrails | pattern | Guardrails | Deterministic checks applied to model inputs and outputs, enforcing constraints that the model itself cannot be relied upon to respect. |
| Human in the Loop HITL | pattern | AI-Era Architecture | Requiring human review or approval at a defined point in an automated flow, chosen by the reversibility and cost of the action. |
| Human-in-the-Loop Design | pattern | Human in the Loop | Placing human review at the points where model error is consequential, designed so the review is genuinely effective rather than nominal. |
| Hybrid Retrieval Dense + Sparse Retrieval, BM25 + Vector | pattern | RAG Architecture | Running lexical keyword search and dense vector search together and fusing the results, because each fails where the other succeeds. |
| Indirect Prompt Injection | concept | Prompt Injection Defence | An attack in which malicious instructions are placed in content the model will later retrieve, rather than typed by the user. |
| Inference Cost per Interaction | metric | AI Cost Management | The fully loaded token cost of one user interaction, including retrieval, retries, guardrails and agent loops, measured rather than estimated. |
| Inference Request Path | concept | LLM Application Architecture | The sequence of stages an LLM application request passes through, each with distinct latency, cost and failure characteristics. |
| Inference Telemetry | practice | AI Observability | Recording the full context of each model interaction — inputs, outputs, tokens, latency, model version and evaluation scores — so quality and cost can be investigated. |
| 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… |
| Least-Privilege Tooling Bounded Tool Permissions | practice | Prompt Injection Defence | Giving each tool the narrowest possible capability and enforcing authorisation at the tool - the decisive control when a model's instructions can be influenced by untrusted content. |
| LLM Evaluation Evals | practice | AI-Era Architecture | A repeatable measurement of whether an AI system's outputs are good enough, on cases that reflect the actual task. |
| LLM-as-Judge | practice | LLM Evaluation | Using a language model to score another model's outputs against criteria, making evaluation scalable at the cost of introducing the judge's own biases. |
| ML Platform | concept | ML Platform | The infrastructure that makes machine learning repeatable — data, features, training, deployment, monitoring — where the model is the small part. |
| Model Cascade Tiered Inference, Escalation Ladder | pattern | Model Selection | A cheap fast model handling the clear majority of cases with escalation to a larger model or a human for the uncertain ones - usually a large cost reduction with no quality loss, because the expensive path run… |
| Model Context Protocol MCP | protocol | AI-Era Architecture | An open protocol that standardises how AI applications connect to external tools, data sources and prompts. |
| Model Drift Monitoring | practice | AI Observability | Detecting that a deployed model's inputs or performance have shifted away from the conditions it was validated under. |
| Model Router | pattern | AI-Era Architecture | Directing each request to a model chosen by the task's difficulty, cost and latency budget, rather than sending everything to the largest model available. |
| Model Routing | pattern | Model Selection | Directing each request to the cheapest model capable of handling it, rather than sending all traffic to the most capable one. |
| Output Validation Layer | pattern | Guardrails | A deterministic check applied to model output before it is used, treating the model as an untrusted component. |
| Prompt Cache Economics Prefix Cache Break-Even, Cache TTL Selection | practice | AI Cost Management | Deciding what to cache and at which time-to-live by comparing the provider's write premium against its read discount, so a long stable prefix is paid for once rather than on every request. |
| Prompt Injection | concept | AI-Era Architecture | An attack in which text from an untrusted source is interpreted by the model as instructions rather than as data. |
| Prompt Injection Defence | practice | Prompt Injection Defence | Defending systems where untrusted content reaches a language model that can take actions — a problem of privilege, not of filtering. |
| Prompt Registry Prompt Management | tool | AI-Era Architecture | A versioned store of production prompts with their model bindings, parameters and evaluation results, so a prompt change is a reviewable, traceable, reversible deployment. |
| Prompt Regression Suite | practice | Prompt & Version Management | A set of test cases with expected properties, run against a prompt on every change, to detect quality regressions before deployment. |
| Prompt Versioning | practice | Prompt & Version Management | Treating prompts as versioned, reviewed, tested and deployable artifacts rather than as strings edited in place. |
| Quality Proxy Metric Implicit Quality Signal, Behavioural Quality Indicator | metric | AI Observability | A continuously available production signal that moves when answer quality moves - abstention rate, regeneration rate, escalation rate - used to page someone in the hours before a labelled evaluation could ever run. |
| Reranking Cross-Encoder Reranking | pattern | Reranking | Retrieving a wide candidate set cheaply, then reordering it with a more expensive model that scores each candidate against the query directly. |
| Retrieval Evaluation | practice | LLM Evaluation | Measuring whether the right context was retrieved, separately from whether the answer was good, because the two failures need different fixes. |
| Retrieval Grounding Grounded Generation | concept | RAG Architecture | Constraining a model's answer to content retrieved from an authoritative corpus, with citations and an abstention path - so that output quality becomes a retrieval problem rather than a model problem. |
| Retrieval Pipeline Stages | pattern | RAG Architecture | The stages that turn a user question into grounded context — query processing, retrieval, reranking and assembly — each independently tunable. |
| Retrieval-Augmented Generation RAG | pattern | AI-Era Architecture | Retrieving relevant documents at query time and putting them in the model's context, so answers are grounded in your data rather than in training data. |
| Retrieval-Generation Separation Evaluate Retrieval Independently, Two-Stage Debugging | practice | RAG Architecture | Measuring whether the correct passage was retrieved, separately from whether the answer was correct - the single diagnostic that turns unfalsifiable RAG debugging into a specific measurable defect. |
| Review Queue Backpressure Human Queue Saturation, Reviewer Capacity Limit | concept | Human in the Loop | What a human-review step does when cases arrive faster than reviewers can clear them - a decision that must be made per action class in advance, because the alternative is an unplanned auto-approval or an unbo… |
| Semantic Cache | pattern | AI-Era Architecture | Caching model responses keyed by the meaning of the request rather than by its exact text, so near-duplicate questions are served without a model call. |
| Semantic Chunking | practice | Chunking & Retrieval | Splitting documents along their meaning and structure rather than at fixed character counts, because retrieval quality is bounded by chunk quality. |
| Serving Path Divergence Per-Pool Quality Drift, Heterogeneous Fleet Skew | concept | AI Observability | One configuration in a fleet of otherwise identical inference paths behaving differently from its peers - detectable by comparing paths against each other, and invisible to any metric averaged across them. |
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