[daeken]

All compilers turn one form of code into another. Whether that's C to assembly (to machine code), or JavaScript to bytecode to machine code, or Python to Python. Transpiler is just a term referring to a compiler taking one high-level language to another. It's unnecessary because a Coffeescript to JavaScript compiler is a transpiler already; saying "transpiler" there tells you nothing you don't already know.

[omaranto]

The phrase "an A to B compiler" might not gain anything from changing compiler to transpiler, but the phrase "an A compiler" does.