Source : Webster's Revised Unabridged Dictionary (1913)

Cardoon \Car*doon"\ (k[aum]r*d[=oo]n"), n. [F. cardon. The same
   word as F. cardon thistle, fr. L. carduus, cardus, LL. cardo.
   See 3d {Card}.] (Bot.)
   A large herbaceous plant ({Cynara Cardunculus}) related to
   the artichoke; -- used in cookery and as a salad.

Source : WordNet®

cardoon
     n 1: southern European plant having spiny leaves and purple
          flowers cultivated for its edible leafstalks and roots
          [syn: {Cynara cardunculus}]
     2: only parts eaten are roots and especially stalks (blanched
        and used as celery); related to artichokes