Chem. [f. CARBON + OX(YGEN, + -YL = substance.] A name given to the monad group –CO·OH, contained in all the fatty acids; thus Formic acid is H–CO·OH, Acetic acid CH3-CO·OH, Butyric acid C3 H7–CO·OH.
1869. Roscoe, Elem. Chem., 346. Carboxyl we thus regard as contained in all the fatty acids: it is formed by the oxidation of methyl.
1878. Kingzett, Anim. Chem., 33. Hydrogen is replaced by a monad carboxyl group.
