1) Having a valence of 1 2) Univalent 1) Univalent 
• (a.) Having a valence of one; univalent. See Univalent.
(mon″o-va´lәnt) having a valence of one; called also univalent. denoting an antiserum, vaccine, or antitoxin specific for a single antigen or organism.
Mo·nov'a·lent adjective [ Mono- + Latin valens , present participle See Valence .] (Chemistry) Having a valence of one; univalent. See Univalent . 
having titer against only one kind, as in Monovalent Antivenin. Only effective against the venom of one particular genus or species.
Type: Term Pronunciation: mon′ō-vā′lent Definitions: 1. Having the combining power (valence) of a hydrogen atom. 2. Pertaining to a monovalent (specific) antiserum to a single antigen or organism. Synonyms: monatomic2, univalent
[adj] - (immunology) containing only one kind of antibody 2. [adj] - (chemistry) having a valence of 1
adj. applied to antivenom, acting against a single type of venom [c.f. polyvalent]
univalent. · · containing only one kind of antibody. · pertaining to an antibody fragment with one antigen-binding site.