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.