Source : Webster's Revised Unabridged Dictionary (1913)

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.

Source : WordNet®

acanthus
     n : any plant of the genus Acanthus having large spiny leaves
         and spikes or white or purplish flowers; native to
         Mediterranean region but widely cultivated
     [also: {acanthi} (pl)]

acanthi
     See {acanthus}