Pronunciation: (trī-môr'fiz-um),[key] —n. 1. Zool.the occurrence of three forms distinct in structure, coloration, etc., among animals of the same species.
2. Bot.the occurrence of three different forms of flowers, leaves, etc., on the same plant or on distinct plants of the same species.
3. Crystall.the property of some substances of crystallizing in three structurally distinct forms.
4. the property or condition of occurring in three distinct forms.