Acanthus \A*can"thus\, n.; pl. E. {Acanthuses}, L. {Acanthi}. [L., from Gr. ?. Cf. {Acantha}.] 1. (Bot.) A genus of herbaceous prickly plants, found in the south of Europe, Asia Minor, and India; bear's-breech. 2. (Arch.) An ornament resembling the foliage or leaves of the acanthus ({Acanthus spinosus}); -- used in the capitals of the Corinthian and Composite orders.