Glossary This glossary provides short definitions for frequently used terms in the Quality Atlas. ACID Atomicity, Consistency, Isolation, Durability — guarantees for transactional systems. CAP Theorem Describes trade-offs between consistency, availability, and partition tolerance. CQRS Separates command handling from query handling. Event Sourcing Stores system state as a sequence of events. Idempotency Ensures that repeated operations produce the same result. Observability Ability to understand system behavior through logs, metrics, and traces. Load Balancing Distributes traffic across multiple instances. Circuit Breaker Prevents repeated failures from cascading. Sharding Splitting data across multiple storage units.