Transpiler is a pretty old word too. My understanding is that it's a compiler whose output is human readable. Readability is more about whether it is an explicit goal: all compiler output is readable by some humans.
I don't think anyone would say Unity's il2cpp is a transpiler even though it compiles .net bytecode into C++: producing readable C++ is a non-goal for il2cpp.
I don't think anyone would say Unity's il2cpp is a transpiler even though it compiles .net bytecode into C++: producing readable C++ is a non-goal for il2cpp.