Although the following (from Wikipedia) seems to accord with usage:
> The name compiler is primarily used for programs that translate source code from a high-level programming language to a lower level language (e.g., assembly language, object code, or machine code) to create an executable program.
Maybe we should complicate that a bit by saying that a compiler typically compiles a programming language into a grammar where the higher-level features of the source language must be "expanded" or "linearized" in some substantial way to be expressed in the target language.
So, for example, GHCJS is more like a compiler than a transpiler, even though its target language is JavaScript, because the JavaScript that it generates is full of graph reduction stuff that is implicit in the source Haskell.
On the other hand, CoffeeScript is more like a transpiler, because it doesn't do any such substantial expansion or linearization.
