The Collaborative International Dictionary
Acetous acid
Acetous \A*ce"tous\ (#; 277), a. [L. acetum vinegar, fr. acere to be sour.]
Having a sour taste; sour; acid. ``An acetous spirit.''
--Boyle. ``A liquid of an acetous kind.''
--Bp. Lowth.-
Causing, or connected with, acetification; as, acetous fermentation.
Acetous acid, a name formerly given to vinegar, which is a dilute solution of acetic acid.
Wiktionary
acetous acid
n. A name formerly given to vinegar.