- _aggregate_: a collection of _entities_ that cluster around a single root entity, referred to as the _aggregate root_.
- _aggregate root_: the entity whose _uuid_ corresponds to the _uuid_ that identifies the entire _aggregate_
- _command_: a message corresponding to a request to change the state of an _aggregate_.
- _entity_: some data with an associated _uuid_.
- _event_: a message that records an _aggregate_'s state transition.
- _event log_: an append-only record of all the events applied to the domain model.
- _read model_: read-optimized caches that are subscribed to updates on the _write model_. Multiple _read models_ can subscribe to a single read model. 
- _uuid_: a universally unique identifier.
- _write model_: the source of truth of the state of a domain. This is often an _event log_.