In chemistry, an oligomer consists of a finite number of monomer units (ολιγος, or oligos, is Greek for "a few"), in contrast to a polymer which, at least in principle, consists of an unbounded number of monomers.

In biochemistry, the term oligomer is used for short, single stranded DNA fragments, generally used in hybridization experiments (bound to glass slides or nylon membranes). It can also refer to a protein complex made of two or more subunits. In this case, a complex made of several different protein subunits is called a hetero-oligomer. When only one type of protein subunit is used in the complex, it is called homo-oligomer.

In oligomerization a chemical process only converts monomers to a finite degree of polymerization. The actual figure is a matter of debate, often a value between 10 and 100.

See also

• Protein quaternary structure