\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.