Oligomers

thumb|right|The 15-crown-5 [[crown ether, a cyclic oligomer, and its monomer, ethylene oxide.]] In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers. The name is composed of Greek elements oligo-, "a few" and -mer, "parts". An adjective form is oligomeric.

A pentamer is an entity composed of five subunits.

Telomerization is a reaction that produces a particular kind of oligomer with two distinct end groups. The oligomer is called a telomer. Some telomerizations proceed by radical pathways, many do not. A generic equation is: where M is the monomer, and A and B are the end groups, and n is the degree of polymerization.

Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended investigation.