The Collaborative International Dictionary of English v.0.48:
monocarbonic \mon`o*car*bon"ic\, monocarboxylic \mon`o*car*box*yl"ic\, a. [Mono- + carbonic.] (Chem.) Containing one carboxyl group; as, acetic acid is a monocarbonic acid. The more common term is monocarboxylic. Contrasted with dicarboxylic, tricarboxylic, etc. [1913 Webster +PJC]WordNet (r) 3.0 (2006):
monocarboxylic adj 1: containing one carboxyl group