A part of a molecule or macromolecule endowed with sufficient
anisotropy in both attractive and repulsive forces to contribute
strongly to
mesophase or, in particular,
liquid-crystal mesophase
formation in low-molar-mass and
polymeric substances.
Source:
PAC, 2002, 74, 493
(Definitions of basic terms relating to polymer liquid crystals(IUPAC Recommendations 2001))
on page 497