Maybe so, but personally it seemed to be referred to as a "specification" or "spec" for a long time, and then suddenly around maybe 5 years ago I started to hear people use "PRD". I'm not sure what caused the change.

Yep, software specs or requirements[0]. Thanks to LLMs it's easy to look up acronyms, but still, it feels like there's an uptick of them on HN[1]...

[0] https://en.wikipedia.org/wiki/Software_requirements_specific...

[1] https://news.ycombinator.com/item?id=47323316 who the hell knows that version of "RSI"?