Probably on topic here - I talk like an LLM sometimes, and parse my points through them sometimes. I’d reasonably use that terminology and think nothing of it as it’s precise and correct. That said, this was partially LLM and my thinking here.

I guess I'm an LLM then. I've been referring to the structure of types as "shape" for more than a decade and so have plenty of others

No it is not. If you were introduced to the term via LLMs doesnt mean everyone was.