Source : Webster's Revised Unabridged Dictionary (1913)

Xanthium \Xan"thi*um\, n. [NL., fr. Gr. xa`nqion a plant used
   for dyeing the hair yellow, said to be the {Xanthium
   strumarium}, from xanqo`s yellow.] (Bot.)
   A genus of composite plants in which the scales of the
   involucre are united so as to form a kind of bur; cocklebur;
   clotbur.

Source : WordNet®

Xanthium
     n : coarse herbs having small heads of greenish flowers followed
         by burrs with hooked bristles [syn: {genus Xanthium}]