Source : Webster's Revised Unabridged Dictionary (1913)

Acetous \A*ce"tous\ (#; 277), a. [L. acetum vinegar, fr. acere
   to be sour.]
   1. Having a sour taste; sour; acid. ``An acetous spirit.''
      --Boyle. ``A liquid of an acetous kind.'' --Bp. Lowth.

   2. Causing, or connected with, acetification; as, acetous
      fermentation.

   {Acetous acid}, a name formerly given to vinegar