[f. as prec. + -ISM]. Cf. F. trichroïsme.] The property of being trichroic: spec. a. Cryst.: see prec.
1847. Webster cites Dana.
1860. in Mayne, Expos. Lex.
1865–8. Watts, Dict. Chem., III. 670. Some biaxial crystals exhibit trichroïsm; thus certain Brazilian topazes of a yellowish rose tint in the direction of the median line, are violet when viewed along the complementary line, and yellowish white perpendicular to the plane of the axes.
1831. S. P. Thompson, in Nature, 15 Sept., 465/2. Crystals in which the electric conductivity differs in three different directions will exhibit trichroism.
b. Nat. Hist. The occurrence of three different colorations in three varieties of a species, as in certain birds and insects.
1899. Sharp, in Cambr. Nat. Hist., VI. vi. 351. H[eliconius] erato exhibits the very rare condition of trichroism, the hind wings being either red, blue, or green.
