Domain terms are domain concepts that exist within the business context. Typically (but not exclusively), they include:

  1. Nouns that appear in both domain commands and domain events.
  2. Tangible entities observable in the real world, even in the absence of an information system (e.g., orders).
  3. Abstract business concepts that may not currently exist but can be conceptualized in the future.
Role Domain Command Domain Event Impact Frequency Domain Terms
Librarian Add Book New Book Added Update book inventory, create book records Immediate Book
User Create Membership Account Member Registered Create member profile, send welcome email Immediate Account, Welcome Notification
Member Borrow Book Book Borrowed Update book status, record borrowing details Immediate Book, Borrowing Record
Member Return Book Book Returned Update book status, clear borrowing record Immediate Book, Borrowing Record
System Send Overdue Reminder Overdue Notification Notify member, calculate fines Immediate + Daily Overdue Notification, Borrowing Record, Fine
Member Reserve Book Book Reserved Create reservation record, update book status Immediate Reservation Record, Book
Member or Librarian Report Lost Book Lost Book Reported Update book status, trigger compensation process Immediate Book, Borrowing Record, Lost Notification

This domain term template demonstrates how to identify key business concepts, i.e., domain terms, through events and commands.