Acetic \A*ce"tic\ (#; 277), a. [L. acetum vinegar, fr. acere to be sour.]

(Chem.)
   (a) Of a pertaining to vinegar; producing vinegar; producing vinegar; as, acetic fermentation.
   (b) Pertaining to, containing, or derived from, acetyl, as acetic ether, acetic acid. The latter is the acid to which the sour taste of vinegar is due.

Source: Webster's Revised Unabridged Dictionary (1913)