Where does “уксус” come from?

уксус (Russian) comes from Old East Slavic уксусъ, from Ancient Greek ὄξος, from Ancient Greek ὀξύς, from Proto-Indo-European h₂eḱ- — sharp.

уксус (Russian): vinegar

Definitions

Step	Language	Word	Meaning
1	Old East Slavic	уксусъ	—
2	Ancient Greek	ὄξος	poor wine; vinegar made therefrom; sour fellow,...
3	Ancient Greek	ὀξύς	sharp, pointed; sharp, keen; quick, hasty, swift
4	Proto-Indo-European	h₂eḱ-	sharp

уксус — Etymology, Origin & Word History | Etymology Explorer