Terminology

2185 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 areas2185 Architecture Fundamentals77 Distributed Systems107 Data Architecture110 Cloud Architecture89 Networking88 API & Integration Architecture82 Reliability & Resilience75 Observability70 Performance & Capacity Engineering72 Security Architecture81 Cost Architecture & FinOps66 Business Architecture67 Architecture Communication67 Enterprise Architecture66 Legacy Modernization66 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 concept785 practice729 pattern362 metric125 case-study77 tool62 protocol45

110 terms shown.

Term	Kind	Topic	What it is
Multi-Leader Replication Multi-Master, Active-Active Replication	pattern	Replication	Accepting writes at more than one node and replicating between them, which removes the single-primary bottleneck and introduces write conflicts.
Netflix's Recommendation Architecture	case-study	Data Architecture	Netflix splits personalisation into offline, nearline and online layers so that expensive computation happens ahead of time and the request path stays fast.
Normalisation Normal Forms	practice	Relational Modelling	Organising a schema so each fact is stored exactly once, removing the update anomalies that duplication creates.
NoSQL Stores Non-Relational Databases	concept	NoSQL Stores	Storage engines that trade query flexibility and cross-entity transactions for predictable performance at scale under known access patterns.
OLTP vs OLAP	concept	Data Warehousing	Two workload shapes with opposite requirements — many small indexed transactions versus few large scans and aggregations — which is why they belong in different stores.
Operational vs Analytical Store	concept	Polyglot Persistence	The separation between the store serving the application's transactions and the one serving reporting and analysis, and the mechanism connecting them.
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.
Partitioning and Sharding	concept	Partitioning & Sharding	Splitting data by a key — within one database for manageability, or across databases for capacity and isolation.
Pattern Scope Discipline Apply the Pattern to a Use Case, Not the System	concept	CQRS	The rule that heavyweight data patterns - CQRS, event sourcing, materialised read models - belong to the specific part of a domain that needs them, never to a whole product.
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.
Polyglot Persistence	concept	Polyglot Persistence	Using different storage engines for different workloads within one system — justified by genuine workload divergence, and frequently not.
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.
Query Optimisation	practice	Query Optimisation	Making the database do less work — usually by removing round trips and rows rather than by rewriting clever SQL.
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-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.
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 Replica	pattern	Data Architecture	A copy of a database that receives changes from the primary and serves read-only queries, spreading read load.
Relational Modelling	practice	Relational Modelling	Designing a schema around entities, relationships and enforced constraints — still the correct default for most transactional systems.
Replica Lag Routing Read Routing, Primary Pinning	practice	Replication	Deciding, per read, whether it may be served by an asynchronous replica - the operational discipline that makes read scaling safe.
Replication	concept	Replication	Keeping copies of data on multiple machines for availability, read scaling and locality — and the lag that comes with all three.
Replication in Practice Read Replicas, Multi-Primary	pattern	Replication	Copying data across nodes for availability and read capacity, and the lag that turns into user-visible bugs if session guarantees are not designed in.
Replication Lag	metric	Replication	How far behind a replica is, measured in time or in log position — the quantity that determines how stale a replica read can be.
Request Coalescing Request Collapsing, Single-Flight	practice	Caching Strategies	Collapsing many concurrent requests for the same missing resource into a single upstream fetch, with the rest waiting on its result.
Reservation Ledger Stock Ledger, Reserve-Then-Commit	pattern	Transactions & Isolation	Modelling stock as an append-only sequence of reservations, releases and allocations rather than as a mutable count - so the number has a history, can be reconciled, and does not become a single point of contention.
Salesforce's Metadata-Driven Multi-Tenancy	case-study	Data Architecture	Salesforce serves every customer from shared infrastructure with a single physical schema, storing customer-specific data structures as metadata rather than as separate tables.
Schema Evolution	concept	Data Lakes & Lakehouses	Changing a table's structure over time while keeping existing data readable and existing consumers working.
Shard Key Partition Key	practice	Partitioning & Sharding	The attribute deciding which partition a row belongs to - the single most consequential and least reversible choice in a partitioned data architecture.
Sharding Horizontal Partitioning	pattern	Data Architecture	Splitting one dataset across multiple independent databases by a partition key, so that each holds a disjoint subset.
Sharding in Practice Horizontal Partitioning	pattern	Partitioning & Sharding	Splitting data across independent stores, how to choose the key, and why resharding is the operation nobody plans for.
Slack Flannel: Caching at the Edge for a Chat Client Flannel	case-study	Caching Strategies	Slack pushed user and channel metadata into an application-aware edge cache because clients were downloading enormous amounts of it on every connection.
Snapshotting	pattern	Event Sourcing	Periodically storing an aggregate's computed state so it can be loaded without replaying its entire event history.
Star Schema	pattern	Data Warehousing	A dimensional model with one central fact table of measurements surrounded by denormalised dimension tables describing them.
Streaming Data Architecture	concept	Streaming Data	Processing unbounded data continuously, where the central problems are time semantics, lateness and state rather than throughput.
Surrogate Key Synthetic Key	concept	Relational Modelling	A system-generated identifier with no business meaning, used as the primary key instead of a naturally occurring business value.
Synchronous vs Asynchronous Replication	concept	Replication	Whether a write is acknowledged only after a replica has it, trading write latency against the amount of data a failure can lose.
Tenant Placement Hybrid Tenancy, Shared-to-Dedicated Migration	pattern	Partitioning & Sharding	Routing each tenant to a shared pool or a dedicated database according to its size and requirements, with an online migration path between them - the hybrid model that neither all-shared nor all-dedicated can match.
Time Travel Data Versioning, Snapshot Query	concept	Data Lakes & Lakehouses	Querying a table as it existed at a previous version or timestamp, made possible by keeping the metadata and files of prior commits.
Transactions and Isolation ACID Isolation Levels	concept	Transactions & Isolation	What a database guarantees when concurrent transactions touch the same data — and the anomalies each level permits.
Two-Phase Locking 2PL	protocol	Transactions & Isolation	The concurrency control protocol behind serializable isolation — acquire locks in a growing phase, release only in a shrinking phase, never interleaving the two.
Uber H3: Hexagonal Spatial Indexing H3, Hexagonal Hierarchical Index	case-study	Indexing	Uber built and open-sourced a hexagonal grid index because uniform neighbour distance matters when you are analysing supply and demand across space.
Uber's H3 Spatial Index	case-study	Data Architecture	Uber indexes the world with hexagons rather than squares, because uniform neighbour distance makes supply, demand and pricing computations correct as well as fast.
Versioned Dataset Swap Atomic Pointer Flip, Generation Swap, Blue-Green Data	pattern	Data Architecture	Publishing a regenerated dataset as a complete new version alongside the live one and flipping a serving pointer atomically, so readers never observe a mixture of generations and rollback is a pointer flip rat…
Wide-Column Store	tool	NoSQL Stores	A store organised as partitions of sorted rows, designed for very high write throughput and predictable single-partition reads at large scale.
Windowing	concept	Streaming Data	Grouping an unbounded stream into finite chunks so aggregation can produce results, defined over event time rather than arrival time.
Workload Class Isolation Compute Separation by Class, Interactive vs Batch Pools	pattern	Data Lakes & Lakehouses	Running interactive, scheduled and batch analytical workloads on separate compute over shared storage, so that a long-running job cannot make an analyst's query unpredictable.
Write Amplification	concept	Partitioning & Sharding	One logical write producing many physical writes - through fan-out, indexes, replication or storage-engine mechanics - and why it decides scaling limits.
Write Skew	concept	Transactions & Isolation	An anomaly where two transactions each read a set of rows, make disjoint writes based on what they read, and together violate an invariant neither could have broken alone.
Write-Ahead Log WAL, Commit Log	concept	Data Architecture	Recording every change to a durable sequential log before applying it, so that a crash can be recovered by replaying the log.
Write-Amplification Audit Index Cost Review, Write Path Accounting	practice	Query Optimisation	Accounting for everything a single logical write actually costs - indexes, replication, triggers, deletion of old rows - before concluding that a database needs more capacity.