\Pro`pi*on"ic\, a. [Proto- + Gr. pi`wn fat.] (Chem.)
Pertaining to, derived from, or designating, an organic acid
which is produced in the distillation of wood, in the
fermentation of various organic substances, as glycerin,
calcium lactate, etc., and is obtained as a colorless liquid
having a sharp, pungent odor. Propionic acid is so called
because it is the first or lowest member of the fatty acid
series whose salts have a fatty feel.