o·pun·ti·a (ō-pŭn'shē-ə, -shə) n. Any of various cacti of the genus Opuntia, especially the prickly pear.
[Latin (herba) Opūntia, Opuntian (herb), feminine of Opūntius, of Opus, an ancient town of east-central Greece, from Opūs, Opūnt-, Opus, from Greek Opous, Opount-.]