The Collaborative International Dictionary of English v.0.48:
Corm \Corm\ (k[^o]rm), n. [See Cormus.] 1. (Bot.) A solid bulb-shaped root, as of the crocus. See Bulb. [1913 Webster] 2. (Biol.) Same as Cormus, 2. [1913 Webster]WordNet (r) 3.0 (2006):
corm n 1: solid swollen underground bulb-shaped stem or stem base and serving as a reproductive structure