1. Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds. (Brittanica) 2. polymerization is process by which molecular entity of small mass are aggregated in motifs over the course of a chemical reaction catalyzed by enzymes or other molecular entities acting as catalyst. polymerization results in molecular entity of high molecular weight (TIB, Ontology for Biomedical Investigations)