any shrub or herbaceous plant of the genus Acanthus, native to the Mediterranean region but widely cultivated as ornamental plants, having large spiny leaves and spikes of white or purplish flowers: family Acanthaceae
See also bear's-breech
2.
a carved ornament based on the leaves of the acanthus plant, esp as used on the capital of a Corinthian column
Word origin
C17: New Latin, from Greek akanthos, from akantha thorn, spine