E.g. in a domain model with two aggregate roots:

  • book
  • author

Is there a specific term that refers to a collection of aggregates of the same root type (e.g. a collection of books)?

In Confusion about the meaning of the word aggregate in domain driven design I read the term aggregate type, which might or might not fit, but I haven't found a direct mention in Evan's blue book.

  • 2
    AFAICT, it's simply a collection of aggregates. Martin Fowler states an invoice as an example of an aggregate, so a bunch of them would simply be a collection of invoices. Jan 8, 2016 at 15:43
  • Is BoundedContext what you're looking for? martinfowler.com/bliki/BoundedContext.html
    – programmer
    Jan 8, 2016 at 16:41
  • @RobertHarvey Thanks for your reply. Would you agree with VoiceOfUnreason that this is because the term aggregate is solely used to describe the concept of a transactional unit and thus there is no need to have a specific term for a collection of those (compared e.g. to table/row in a database context)?
    – sthzg
    Jan 9, 2016 at 12:54
  • @Jason Bounded Contexts are not really what I was after. With the distance of one day I realized that my question wasn't all that precise because I was really looking for something different. :) But that's a bit too far away from my original question so I leave that as it is and may be opening a follow up sometime. Nevertheless I find the question as is also interesting, namely if there was a specific term for a collection of aggregates of the same root type (seems there is none according to the answers).
    – sthzg
    Jan 9, 2016 at 13:00
  • Table/Row is also a collection. It just happens to be a collection in a database, and table/row are convenient terms for something that has that particular shape. Jan 9, 2016 at 15:06

1 Answer 1


Is there a specific term that refers to a collection of aggregates (e.g. books or authors)?


Keep in mind that the definition of aggregate is

A cluster of associated objects that are treated as a unit for the purpose of data changes. External references are restricted to one member of the aggregate, designated as the root. A set of consistency rules applies within the aggregate's boundaries.

A union of two different transactional units is... not very interesting.

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