[c0balt]

A transpiler is just a piece of software that translates code to code. A compiler is a transpiler that targets machine code and usually builds an executable through various pipelines, e.g. optimization passes etc.

Transpilers aren't limited to JS nor web dev. There are various other transpilers/compilers such as nimlangs compiler that can target C.

[naniwaduni]

A compiler and a transpiler are the exact same thing, technically; the words differ in their connotations. And the communities you participate in definitely inform word choice.

(Parts of the Nim community are famously insistent that they have a compiler, not a transpiler!)

[dgb23]

It's the other way around. A transpiler is a compiler that compiles code from one to another high level language. Compiler is the more general term here.

The distinction is almost arbitrary and rarely used until recently I think. It would be more useful if "transpiler" had some well defined property (like isomorphism) that distinguishes it from a compiler other than targeting a "high level" language. Are C, JVM bytecode, WASM, LLVM IR etc "high level" or not?

It gets even more confusing. In the JS world "transpiling" is for example used to describe the process of rewriting code from one version of the spec to another for compatibility reasons. What does that say about "npm fix" or "go fix"? Are those transpilers too? Does that mean they are compilers? What about a Lisp macro? An SQL query builder? Some of these do more involved things than what is called "transpiling" in the JS world.