Loudness is now very specifically defined using LUFS (Loudness Units Full Scale) and it's essential if you're mastering audio and want it to sound good on different platforms. The scale takes into account absolute signal level, the frequency response of human hearing, and a few other technical factors. There's a relatively simple introduction here: https://emastered.com/blog/what-are-lufs
Somewhere I have a really good cheat sheet translating a lot of common terms musicians use into something that sound engineers can adjust, but I can't find it. Will keep looking.
Edit: this attachment isn't the one I was looking for and doesn't define thump, but it might be useful to someone.
FrequencyCheetsheet.pdf