Sorry but can you point to the particular use of "transpiler"?

I've skimmed this several times and have now run it through a PDF OCR program, and am not finding it.

Even if this paper does use the term saying "we've been using it all along!" is hardly accurate because this has hardly been a well-known term until very recently - I've read hundreds of academic compilers (mostly on the optimization & code generation side of things) going back to the late fifties, and it's only a term I've seen used in the very recent past.

The second to last paragraph. And they use the term in quotes which makes it appear like it could have been new at that time.

Transpiler means high-level to high-level translation. Compilers which implement such a translation have properties and challenges in common. It's a subset of compiler. I don't know how anyone can think it's wrong to have a term, whether it's new or not, to refer to a useful subset like that.

What harm or misunderstanding could it possibly cause?

Thanks for pointing out the reference - the OCR apparently stopped part-way through the document.

The harm comes from having a definition that is so loose as to be meaningless. You're now saying "high-level to high-level", but most people use the terms "source language to source language", and several people here have admitted that a compiler that generates assembly should be considered a transpiler.

If you're going to define it as something that goes from a "high-level" language to another, then you need to define high level. Is C high level? is C++? is HLSL (there are lots of HLSL <-> GLSL translators)?

Also, in almost every context that I see "transpiler" used, people say that it's a transpiler from X-to-Y, which adds zero value above saying it's a compiler from X-to-Y.

People usually don't feel the need to qualify what they are compiling from or to, despite the fact that many compilers target (or use as a source) many kinds of languages and/or intermediate representations.

The overall point here is that compilers (of all kinds) are simply translators - some from a high level source language to one form of (textual or otherwise) IR, some from one form of IR to another, some from one source language to another (be it high level or not), etc. Saying one is a "transpiler" and others are not, especially when you give adequate context and say what the source and destination forms are, just doesn't add value.