Terminology

681 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 areas681 Architecture Fundamentals38 Distributed Systems73 Data Architecture71 Cloud Architecture55 Networking51 API & Integration Architecture45 Reliability & Resilience40 Observability33 Performance & Capacity Engineering34 Security Architecture50 Cost Architecture & FinOps12 Business Architecture9 Architecture Communication8 Enterprise Architecture8 Legacy Modernization11 AI-Era Architecture34 Software Architecture & Engineering37 Architecture Patterns34 Architecture Decision-Making30 The Architect's Meta-Skills8

Kind Any concept258 practice180 pattern127 protocol32 tool32 case-study26 metric26

681 terms shown.

Term	Kind	Topic	What it is
Paved Road Golden Path	practice	Enterprise Architecture	A supported, opinionated default way to build and run a service, made easy enough that teams choose it rather than being required to.
Payload Compression Trade-off	concept	Network Performance Tuning	The exchange of CPU time for reduced transfer time, which is favourable on constrained networks and harmful on fast local ones.
Percentile Latency	metric	Latency	Latency expressed as the value below which a given proportion of requests fall, used because averages conceal the behaviour that users notice.
Performance Budget	practice	Performance Budgets	A stated numeric limit on a performance characteristic, enforced automatically so that regressions fail a build rather than accumulating.
Permission Boundary	concept	Identity & Access Management	A policy limiting the maximum permissions an identity can have, used so that the ability to create roles does not become the ability to grant unlimited privilege.
Persisted Query	pattern	GraphQL	Registering allowed queries in advance and having clients send an identifier instead of the query text.
Personally Identifiable Information PII, Personal Data	concept	Security Architecture	Data relating to an identifiable person — a category far broader than name and address, and the trigger for most regulatory obligation.
Pilot Light	pattern	Disaster Recovery	A disaster recovery posture where core data is continuously replicated and minimal infrastructure runs, with the rest provisioned only on failover.
Pinterest's MySQL Sharding	case-study	Data Architecture	Pinterest sharded MySQL by embedding the shard ID inside every primary key, making any object's location computable from its ID alone with no lookup service.
Pipeline Orchestration	practice	ETL & ELT	Coordinating the execution of data tasks by dependency rather than by clock, with retries, backfill and observability built in.
Pipes and Filters	pattern	Architecture Patterns	Decomposing processing into independent steps connected by channels, each transforming its input and passing it on.
Pivot Transaction	concept	Sagas & Compensation	The step in a saga after which the transaction can no longer be cancelled — everything before it is compensatable, everything after it is retriable until it succeeds.
Pod	concept	Kubernetes	The smallest deployable unit in Kubernetes — one or more containers that share a network namespace, storage volumes and a lifecycle, scheduled together on one node.
Point-in-Time Recovery PITR	concept	Backup Strategies	Restoring a database to any moment within a retention window by replaying transaction logs onto a base backup, rather than only to a snapshot boundary.
Policy as Code	practice	Cloud Governance	Expressing governance rules as executable code evaluated automatically, so compliance is prevented at creation rather than reported after the fact.
Port and Adapter	pattern	Hexagonal Architecture	An interface defined by the application expressing what it needs, paired with an implementation that connects it to a specific technology.
Port Exhaustion	concept	NAT & Egress	Running out of available source ports for outbound connections through a NAT device, causing new connections to fail while everything appears healthy.
Pragmatism	practice	Meta-Skills	Preferring the simplest architecture that satisfies the requirements, and treating additional structure as a cost that must be justified.
Pre-Provisioned Capacity	pattern	Static Stability	Running capacity that is already in place to absorb a failure, rather than depending on a control plane to create it during the failure.
Pre-Scaling	practice	Peak Event Readiness	Provisioning capacity in advance of a known traffic event rather than relying on autoscaling to react to it.
Presenting to Engineers	practice	Architecture Communication	Presenting a design at the level of mechanism, including the alternatives rejected and the parts you are still unsure about.
Presenting to Executives	practice	Architecture Communication	Leading with the decision and the business consequence, at a level of abstraction where technology names do not appear.
Prime Video's Move Back to a Monolith Prime Video VQA Rearchitecture	case-study	Architecture Patterns	Amazon Prime Video consolidated a serverless, distributed audio/video monitoring service into a single process and reported a 90% cost reduction — the most-cited example of microservices being the wrong tool.
Principle Rationale	practice	Architecture Principles	The stated reasoning and implications attached to an architecture principle, without which the principle cannot be applied to a case its authors did not foresee.
Priority Queueing	pattern	Load Shedding	Classifying requests by business importance so that overload sheds the least valuable work first rather than an arbitrary slice.
Privacy by Design	practice	Security Architecture	Building privacy protections into a system's structure from the start, rather than adding controls to a design that already collects and keeps everything.
Private Endpoint PrivateLink, VPC Endpoint	concept	Private Connectivity	A private network address inside your VPC that reaches a managed service directly, without traversing the internet or a NAT gateway.
Problem Details RFC 9457, RFC 7807	protocol	API Error Handling	A standard JSON structure for HTTP error responses, giving machine-readable type, human-readable detail, and room for extensions.
Process Manager	pattern	Orchestration vs Choreography	A component that owns the state and sequencing of a multi-step business process, deciding what happens next in response to events.
Product Thinking	practice	Business Architecture	Treating what you build as something with users, a value proposition and a lifecycle, rather than as a project that completes.
Projection	pattern	CQRS	The process that consumes changes from the write side and maintains a read model, and the component where most CQRS bugs live.
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 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	AI-Era Architecture	Treating prompts as versioned, reviewed, tested artefacts rather than as strings edited in place.
Protocol Buffers Protobuf	protocol	gRPC Transport	A binary serialisation format with a schema definition language, generating typed code and enforcing explicit compatibility rules through field numbering.
Provider Verification	practice	Contract Testing	The provider-side stage that replays every consumer's recorded expectations against the real implementation.
Provisioned vs Serverless Capacity	concept	Cloud Databases	Paying for a fixed database size continuously, versus paying for capacity consumed with automatic scaling — a crossover decision driven by duty cycle.
Proxy Buffering	concept	Reverse Proxies	Whether a reverse proxy accumulates a response before forwarding it, which protects the backend from slow clients but breaks streaming.
Publish/Subscribe Pub/Sub	pattern	Architecture Patterns	A messaging pattern where each published message is delivered to every interested subscriber, rather than to one competing worker.
Purpose Limitation	concept	Privacy Engineering	The principle that personal data collected for one stated purpose may not be used for an unrelated one without a new lawful basis.
Quality Attribute Scenario QAS	practice	Architecture Fundamentals	A structured, testable statement of a non-functional requirement: source, stimulus, environment, artefact, response, response measure.
Query Plan Execution Plan, EXPLAIN	concept	Data Architecture	The database's chosen strategy for executing a query, and the first thing to look at when one is slow.
Query Plan Regression	concept	Database Performance	A sudden latency increase caused by the database optimiser choosing a different execution plan for an unchanged query, typically after statistics or data volume change.
Query-Based CDC Polling CDC, Timestamp-Based CDC	pattern	Change Data Capture	Detecting changes by repeatedly querying for rows modified since the last run — simple, universally available, and lossy in specific ways.
Queue Length Estimation	practice	Little's Law	Using the relationship between arrival rate, residence time and items in the system to size pools, predict backlogs and sanity-check capacity claims.
QUIC HTTP/3	protocol	HTTP/1.1, HTTP/2 & HTTP/3	A transport built on UDP that provides streams, encryption and congestion control, removing TCP's head-of-line blocking and reducing connection setup latency.
Quorum	concept	Distributed Systems	A minimum number of nodes that must acknowledge an operation for it to count, chosen so that read and write sets are guaranteed to overlap.
Raft	protocol	Consensus Protocols	A consensus algorithm designed to be understandable, decomposing agreement into leader election, log replication and safety.
Rate Limiting	pattern	API & Integration	Bounding how many requests a caller may make in a window, to protect capacity and enforce fair use.
Re-architect vs Rebuild	concept	Legacy Modernization	Restructuring an existing system incrementally versus writing a replacement from scratch — and the strong evidence that incremental wins.
Reactive Streams	protocol	Backpressure & Flow Control	A specification for asynchronous stream processing in which the consumer requests a specific number of items, making backpressure part of the protocol rather than an afterthought.
Read Model Query Model, Projection Store	pattern	CQRS	A data structure shaped for a specific query rather than for the domain, maintained separately from the write model.
Read Model Projection	pattern	CQRS	A denormalised store built and maintained from write-side events specifically to serve one query shape efficiently.
Read Replica	pattern	Data Architecture	A copy of a database that receives changes from the primary and serves read-only queries, spreading read load.
Read Timeout Socket Timeout	concept	Timeouts & Deadlines	The bound on how long a client waits for response data after a connection is established — distinct from the connect timeout, and the one that usually matters.
Read-Your-Writes Consistency Read-After-Write	concept	Consistency Models	A session guarantee that a client always sees its own updates, even when reads are served from replicas that may lag.
Recovery Point Objective RPO	metric	RTO & RPO	The maximum acceptable data loss measured as a duration, determining the replication and backup strategy.
Recovery Time Objective RTO	metric	RTO & RPO	The maximum acceptable duration between a failure and restored service, agreed with the business rather than chosen by engineering.
RED Method	practice	Observability	A minimal per-service dashboard: Rate, Errors, Duration — the request-centric view of whether users are being served.