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

38 terms shown.

Term	Kind	Topic	What it is
Cache Invalidation	concept	Data Architecture	The problem of removing or refreshing cached data when the underlying source changes, and the reason caching is harder than it looks.
Cache Penetration	concept	Cache Invalidation	Repeated lookups for keys that do not exist, which miss the cache every time by definition and pass straight through to the store.
Cardinality Estimation	concept	Query Optimisation	The planner's prediction of how many rows each step of a query will produce — the input that determines every other choice it makes.
CDC Initial Snapshot	concept	Change Data Capture	The consistent full copy taken when a CDC pipeline starts, before streaming begins — and the step that determines whether the target is correct.
Consistent Hashing Ring Hashing	concept	Partitioning & Sharding	A partitioning scheme where adding or removing a node moves only a small fraction of keys, instead of remapping everything.
Covering Index Index-Only Scan	concept	Indexing	An index that contains every column a query needs, so the query is answered from the index without reading the table at all.
Data Lakehouse	concept	Data Architecture	A pattern that puts warehouse-style transactions, schema and governance on top of cheap open-format object storage.
Data Mesh	concept	Data Architecture	An organisational approach that gives domain teams ownership of their analytical data as a product, with a self-serve platform and federated governance.
Data Warehousing	concept	Data Warehousing	A separate analytical store modelled for questions rather than transactions, physically isolated from the systems that generate the data.
Database Index	concept	Data Architecture	A secondary structure that lets the engine find rows without scanning, trading write cost and storage for read speed.
Derived Store Discipline One Authoritative Store Per Fact, No Dual Authority	concept	Polyglot Persistence	The rule that every fact has exactly one authoritative store and every other copy is explicitly derived, rebuildable and populated by a documented pipeline - the discipline that makes multiple datastores defensible.
ETL vs ELT	concept	Data Architecture	Whether data is transformed before loading into the target or after it, which decides where the compute happens and how much raw history you keep.
Foreign Key Constraint	concept	Relational Modelling	A database-enforced rule that a referencing value must exist in the referenced table — referential integrity that no application bug can violate.
Hot Key Hot Partition, Hot Row, Key Skew, Celebrity Problem	concept	Partitioning & Sharding	A single key or narrow key range receiving a disproportionate share of traffic, so one partition saturates while the rest of the cluster is idle - the failure that no amount of horizontal scaling fixes.
Hot Key Hot Partition, Hot Shard	concept	Partitioning & Sharding	A single key or partition receiving a disproportionate share of traffic, so that a well-balanced key space still produces one overloaded node.
Hot Partition Hot Shard, Hot Key	concept	Partitioning & Sharding	One partition receiving disproportionate traffic, so the system saturates at a fraction of its aggregate capacity.
Hot, Warm and Cold Data	concept	Data Lifecycle & Retention	Classifying data by how frequently and how urgently it is accessed, so each tier can be stored on media priced for that access pattern.
Indexing	concept	Indexing	Auxiliary structures that turn a scan into a lookup — the highest-leverage database intervention and the one most often applied blindly.
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.
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.
Polyglot Persistence	concept	Polyglot Persistence	Using different storage engines for different workloads within one system — justified by genuine workload divergence, and frequently not.
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.
Replication	concept	Replication	Keeping copies of data on multiple machines for availability, read scaling and locality — and the lag that comes with all three.
Schema Evolution	concept	Data Lakes & Lakehouses	Changing a table's structure over time while keeping existing data readable and existing consumers working.
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.
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.
Windowing	concept	Streaming Data	Grouping an unbounded stream into finite chunks so aggregation can produce results, defined over event time rather than arrival time.
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.