Terminology

791 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 areas791 Architecture Fundamentals38 Distributed Systems73 Data Architecture71 Cloud Architecture55 Networking51 API & Integration Architecture45 Reliability & Resilience40 Observability33 Performance & Capacity Engineering34 Security Architecture50 Cost Architecture & FinOps30 Business Architecture28 Architecture Communication27 Enterprise Architecture27 Legacy Modernization27 AI-Era Architecture34 Software Architecture & Engineering37 Architecture Patterns34 Architecture Decision-Making30 The Architect's Meta-Skills27

Kind Any concept292 practice240 pattern133 metric36 protocol32 tool32 case-study26

791 terms shown.

Term	Kind	Topic	What it is
Organisational Readiness	concept	Organisational Constraints	Whether an organisation has the skills, capacity, structure and appetite to operate a proposed architecture, independent of the design's technical merit.
Origin Shield	pattern	Content Delivery Networks	An intermediate caching layer between CDN edge nodes and the origin, so a cache miss at many edges results in one origin request rather than many.
Orphaned Resource	concept	Waste Elimination	Infrastructure that is billed but serves nothing, typically left behind when the thing it supported was deleted.
Outbox Pattern Transactional Outbox	pattern	Architecture Patterns	Writing an outgoing message into a table in the same transaction as the business change, and relaying it to the broker separately, so the two cannot diverge.
Outbox Relay	pattern	Outbox	The process that reads pending messages from an outbox table and publishes them to a broker, providing at-least-once delivery with no distributed transaction.
Outcome Measurement	practice	Outcome Measurement	Establishing a baseline before a change and measuring the intended effect afterwards, so that investment decisions are informed by evidence rather than by narrative.
Outcome over Output	concept	Product Thinking	Measuring and committing to changes in user or business behaviour rather than to the delivery of features.
Output Validation Layer	pattern	Guardrails	A deterministic check applied to model output before it is used, treating the model as an untrusted component.
OWASP Top Ten	practice	Security Architecture	A periodically updated consensus list of the most critical web application security risks, useful as a design-review checklist.
PACELC	concept	CAP & PACELC	An extension of CAP that also describes the normal case — if Partitioned choose Availability or Consistency, Else choose Latency or Consistency.
Page and Ticket Routing	practice	Alerting	Deciding for each monitored condition whether it warrants immediate human interruption or asynchronous handling, and enforcing the distinction.
Parallel Run	practice	Legacy Modernization	Running the old and new systems side by side on the same inputs and comparing outputs, before the new one is trusted.
Parallelism and Concurrency	concept	Concurrency	The distinction between structuring work so it can make progress independently and actually executing work simultaneously on multiple cores.
Partial Index Filtered Index	concept	Indexing	An index built over only the rows matching a predicate, so it is far smaller and cheaper to maintain than a full index.
Partition Assignment	concept	Competing Consumers	The mapping of partitions to consumer instances that determines parallelism, ordering guarantees and what happens when the consumer set changes.
Partition Tolerance	concept	CAP & PACELC	The ability to keep operating when the network drops or delays messages between nodes — not a choice, but a property of any system spanning more than one machine.
Partner Onboarding	practice	Partner & B2B Integration	The repeatable process by which an external organisation is connected, tested and moved to production — and a common hidden bottleneck.
Path MTU Discovery PMTUD	concept	Network Troubleshooting	The mechanism by which a sender discovers the largest packet size a path supports, and a common cause of connections that establish and then hang.
Pattern Overuse	concept	Design Patterns	Applying a design pattern where the problem it solves does not exist, adding indirection and vocabulary without benefit.
Pattern Recognition	practice	Meta-Skills	Recognising that a novel-looking problem is an instance of one you have seen before, and knowing which parts of the previous solution transfer.
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.
Platform as a Product	practice	Platform as a Product	Running an internal platform with the disciplines of a product — voluntary adoption, user research, documentation and a roadmap — rather than as a mandated standard.
Platform Team Product Model	practice	Platform Teams	Running an internal platform team with product management disciplines — users, roadmap, support, metrics — rather than as an infrastructure function.
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.
Portfolio Assessment Matrix	practice	Application Portfolio Management	Plotting each application on business value against technical quality, producing a disposition for every system in the estate.
Power-Interest Grid	practice	Stakeholder Analysis	A classification of stakeholders by their influence over a decision and their level of concern with it, used to allocate communication effort deliberately.
Pragmatism	practice	Meta-Skills	Preferring the simplest architecture that satisfies the requirements, and treating additional structure as a cost that must be justified.
Pre-Mortem	practice	Failure Thinking	An exercise in which a team imagines a project has already failed and explains why, surfacing risks that a forward-looking risk assessment misses.
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.
Process Model	concept	Business Processes	A representation of how work actually flows through an organisation, distinguished from a capability by describing sequence, actors and handoffs.
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.