trillium n 1: any liliaceous plant of the genus Trillium having a whorl of three leaves at the top of the stem with a single three- petaled flower [syn: {trillium}, {wood lily}, {wake-robin}]
Trillium \Tril"li*um\, n. [NL.; cf. L. trilix triple-woven, triple.] (Bot.) A genus of liliaceous plants; the three-leaved nightshade; -- so called because all the parts of the plant are in threes. [1913 Webster]