skeletal structure

https://doi.org/10.1351/goldbook.S05708
The sequence of atoms in the constitutional unit(s) of a macromolecule, an oligomer molecule, a block or a chain which defines the essential topological representation.
Source:
PAC, 1996, 68, 2287. 'Glossary of basic terms in polymer science (IUPAC Recommendations 1996)' on page 2296 (https://doi.org/10.1351/pac199668122287)