The Collaborative International Dictionary of English v.0.48:
Urtica \Ur*ti"ca\, n. [L., a nettle.] (Bot.) A genus of plants including the common nettles. See Nettle, n. [1913 Webster]WordNet (r) 3.0 (2006):
Urtica n 1: a nettle yielding fiber resembling flax [syn: Urtica, genus Urtica]