Wordnet 3.0
NOUN (1)
1.
pleochroism of a crystal so that it exhibits three different colors when viewed from three different directions;
The Collaborative International Dictionary of English v.0.48:
Trichroism \Tri"chro*ism\, n. [Pref. tri- + Gr. ? color: cf. F.
trichro["i]sme.] (Min.)
The quality possessed by some crystals of presenting
different colors in three different directions.
[1913 Webster]
WordNet (r) 3.0 (2006):
trichroism
n 1: pleochroism of a crystal so that it exhibits three
different colors when viewed from three different
directions