Nah...IMHO message-passing is a generalization.

The point is that it encompasses all of these things: synchronous, asynchronous, local, distributed, late-bound, early bound, point-to-point, broadcast, multicast.

And ideally, you should be able to select which kind you want on a case-by-case basis. With ease.

Rather than having to choose a different programming language.

i agree with that definition but then smalltalk nor any other language are using message passing for regular method calls because they are not asynchronous unless they use explicitly asynchronous methods.