The Oxford English Dictionary says the following about the etymology of physics:
< PHYSIC adj. (see -ic suffix 2), after classical Latin physica natural science, in post-classical Latin also the science of medicine (c400), and as the title of Aristotle's physical treatises (1267, 15th cent. in British sources), use as noun of neuter plural of physicus physic adj., itself after ancient Greek τὰ ϕυσικά , lit. ‘natural things’, the collective title of Aristotle's physical treatises. Compare Old French, Middle French physique PHYSIC n. Compare earlier PHYSIC n.
What is the relationship between ϕυσικά (in τὰ ϕυσικά) and whatever was the ancient Greek (in Aristotle's time) word for the noun 'nature'? (Is that latter word perhaps φὺσις?) Is one of these two words (ϕυσικά and whatever was the word for 'nature') more 'basic' than the other, or is there a common root?
Why isn't it correct to say that physics ultimately comes from the ancient Greek word for 'nature' (whatever it is)? (I assume it is not correct to say that because if it were, the OED would say it.)