An irregular oligomer, the molecules of which are derived from only one species of monomer but which display a variety of structural features more appropriate for description in co-oligomer terms.
Source:
PAC, 1996, 68, 2287. 'Glossary of basic terms in polymer science (IUPAC Recommendations 1996)' on page 2300 (https://doi.org/10.1351/pac199668122287)