This comes up every time the term is used, but I don't get it. It's hardly the first time we've introduced redundancy in English, and it won't be the last. As

This comes up every time the term is used, but I don't get it. It's hardly the first time we've introduced redundancy in English, and it won't be the last. As to your question, it doesn't really make sense for something to "change" from a transpiler to a compiler, any more than it makes sense to change from a Ford to a car. All transpilers are compilers; "transpiler" is just a little more specific. You know, like "gigantic" is a little more specific than "big", or "square" is a little more specific than "rectangle". FWIW, I disagree with cromwellian that it's anything to do with optimization. I wouldn't personally say CPython transpiles Python to bytecode, but I'd also say an optimized transform from Dart to JS is a transpile. In my eyes, a transpiler is just any compiler where the target language is only intended to be written by humans. (This changes over time, though. I'd probably not call Nim to C a transpile, although I might have in the past. We're probably reaching the point where X to JS stops being a transpile, too.)