Glossary

General

simple entity - a single persistence unit.. "data that can be written atomically"
aggregate entity - a collection of simple entities associated through some relationships
data service - a software service for manipulating a simple entities
orchestration service - synonymous with "aggregation service"
aggregation service - a software service for manipulating aggregate entities
business service - a software service for doing anything outside of data or aggregation service scope. Typically anything that has business logic requirements.

document - structured text representing data for an entity. Unless specified, assume this is referring to a JSON document.
hook - operations that provide a way for CRUD operations to have side effects after a document is created, modified, or deleted. Similar to triggers in a relational database
projection - projection refers to either a document that defines what fields to keep when returning a result set or the result set from such an operation (applying a projection)

movable data - data that can be moved from existing datastores to another location
unmovable data - data that can not be moved from existing datastores