What you'd probably say, and the word that gets you the right answer. Physics is unusually strict about these \u2014 several pairs that sound like synonyms in English mean genuinely different things here.
Physics splits by what's being studied, and the divisions are sharp. Naming the branch tells a helper which set of equations to reach for.
The working vocabulary, grouped by territory. Skim a group before you head into it; search once you're already lost in it.
Physics runs on abbreviations. Here's what each letter stands for and how the units are read aloud.