A monomer (from Greek mono “one” and meros “part”) is a molecule that may bind chemically to other molecules to form a polymer. The term “monomeric protein” may also be used to describe one of the proteins making up a multiprotein complex. The most common natural monomer is glucose, which is linked by glycosidic bonds into polymers such as cellulose and starch, and is over 77% of the mass of all plant matter.