Source : Webster's Revised Unabridged Dictionary (1913)

Margarin \Mar"ga*rin\, n. [Cf. F. margarine. See {Margarite}.]
   (Physiol. Chem.)
   A fatty substance, extracted from animal fats and certain
   vegetable oils, formerly supposed to be a definite compound
   of glycerin and margaric acid, but now known to be simply a
   mixture or combination of tristearin and teipalmitin.

Source : WordNet®

margarin
     n 1: a glyceryl ester of margaric acid [syn: {glycerol
          trimargarate}]
     2: a spread made chiefly from vegetable oils and used as a
        substitute for butter [syn: {margarine}, {oleo}, {oleomargarine},
         {marge}]