(chemistry, physics) Of or pertaining to phases of matter intermediate between solid and liquid; of or pertaining to liquid crystals.
1958, Chemical Society (Great Britain), G. W. Gray, Steric Effects in Conjugated Systems, page 161,
Changes in the chemical constitution of a mesomorphic compound may therefore radically alter the mesomorphic properties and thermal stabilities.
1993, Nikolaĭ Alʹfredovich Platė (editor, original Russian edition), S. L. Schnur (translator), Liquid-Crystal Polymers, page 132,
This x-ray is typical of mesomorphic structures which occupy an intermediate position between crystalline and amorphous with respect to the degree of order.