noun

1. the property that doubly refracting crystals have of transmitting light of different colors when looked at from different angles
2. the property of a substance of transmitting light of different colors depending on its thickness or on its concentration in solution
3. the property of a substance of having one color when it reflects light and another when it transmits light

Etymology: < Gr dichroos, of two colors < di-, two + chrōs, skin, complexion, color (for IE base see chroma) + -ism