A cyclic macromolecular or a macromolecular cyclic portion of a macromolecule.
In the literature, the term 'macrocycle' is sometimes used for molecules of low molecular mass that would not be considered 'macromolecules' as specified in the definition given in this book.
See: chain (Note 2) (in polymers)
PAC, 1996, 68, 2287. 'Glossary of basic terms in polymer science (IUPAC Recommendations 1996)' on page 2298 (https://doi.org/10.1351/pac199668122287)