Cac·tus n. ; pl. E. Cactuses Cacti Bot. Any plant of the order Cactacæ, as the prickly pear and the night-blooming cereus. See Cereus. They usually have leafless stems and branches, often beset with clustered thorns, and are mostly natives of the warmer parts of America.
Cactus wren Zoöl., an American wren of the genus Campylorhynchus, of several species.