'Rhizome' definitions:

Definition of 'rhizome'

(from WordNet)
noun
A horizontal plant stem with shoots above and roots below serving as a reproductive structure [syn: rhizome, rootstock, rootstalk]

Definition of 'Rhizome'

From: GCIDE
  • Rhizome \Rhi*zome"\, n. [Gr. ??? the mass of roots (of a tree), a stem, race, fr. ??? to make to root, pass., to take root, fr. ??? a root: cf. F. rhizome.] (Bot.) A rootstock, such as one of an iris. See Rootstock. [1913 Webster]