The Collaborative International Dictionary of English v.0.48:
Mnium \Mnium\ prop. n. A genus of mosses similar to those of genus Bryum but larger. Syn: genus Mnium. [WordNet 1.5]WordNet (r) 3.0 (2006):
Mnium n 1: mosses similar to those of genus Bryum but larger [syn: Mnium, genus Mnium]