All compilers translate one language to another language. Historically compilers targeted lower-abstraction languages than the source language. "Transpiler" is a compiler whose input and output abstraction levels are similar.

The React cinematic universe has a habit of repurposing existing terminology, but they're both transpilers, to the extent that "transpiler" is even a word.

You are absolutely right! (Here I'm roleplaying an AI chat bot which caught red handed hallucinating).

It appears that I was wrong about the definition of transpilation. It's a specific term for a compiler that compiles from a high-level language to another high-level language, even when those languages are the same with no DSL and even when the logic is optimized.

I stand corrected.

In JS land, transpile was used to distinguish something like elm->JS from ES6->ES3. One was the same language with different versions and the other was different source languages.

Yes, all transpilers are compilers, but not all compilers are transpilers.