The thing is, if you make the definition too generic, everything turns out to be a compiler. For instance, Photoshop is a compiler that turns commands in the UI (the input language) into PSD files (the output language). It's a lot harder to define terms like "compiler" than it actually seems.
And you have to differentiate your definition for 'compiler' from 'interpreter'. And point out, that those two sit on opposite ends of the same spectrum.
Even that is a fuzzy barrier. You have lots of languages that have the compiler built-in to the runtime environment (Smalltalk, and I guess most lisps?). Anything with JIT blurrs the line, too.
