A monomer (/ˈmɒnəmər/ MON-ə-mər) (, "one" + , "part") is a molecule that may bind chemically or supramolecularly to other molecules to form a (supramolecular) polymer. The process by which monomers combine to form a polymer is called polymerization. Molecules made of a small number of monomer units (up to a few dozen) are called oligomers. The term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex.
*Diglycerides and triglycerides are made by dehydration synthesis from smaller molecules; this is not the same kind of end-to-end linking of similar monomers that qualifies as polymerization. Therefore, diglycerides and triglycerides are an exception to the term polymer.
Examples: The most common natural monomer is glucose, which is linked by glycosidic bonds into polymers such as cellulose, starch, and glycogen. Most often the term monomer refers to the organic molecules which form synthetic polymers, such as vinyl chloride, which is used to produce the polymer polyvinyl chloride (PVC).