It's almost as if the experts don't all agree with this terminology.

Edit: This was a bit too snarky, but truthfully, I don't see evidence in the field that these definitions are widely used. I see evidence that an very small crowd is using these terms and asserting their correctness. Meanwhile the rest of the industry thinks anything they use as a "double" in a test is a "mock".

Even the people writing widely-used mocking libraries aren't using this terminology consistently.