This is number 4 in a series of short posts I am writing about "Must Know Dialogflow Features". In this post I talk about composite entities.
And this one is a somewhat complex feature, and it is possible you might never need it.
For the programmers out there, the idea behind composite entities is somewhat similar to how you can have multiple fields in a class.
If you are not a programmer, then think about composite entities as a way to join entities to create a more complex and richer entity type.
You can use composite entities to do some nifty things. For example, you can implement some sophisticated boolean logic inside your training phrases.