Source : Webster's Revised Unabridged Dictionary (1913)

Yucca \Yuc"ca\, n. [NL., from Yuca, its name in St. Domingo.]
   (Bot.)
   A genus of American liliaceous, sometimes arborescent, plants
   having long, pointed, and often rigid, leaves at the top of a
   more or less woody stem, and bearing a large panicle of showy
   white blossoms.

   Note: The species with more rigid leaves (as {Yucca
         aloifolia}, {Y. Treculiana}, and {Y. baccata}) are
         called {Spanish bayonet}, and one with softer leaves
         ({Y. filamentosa}) is called {bear grass}, and {Adam's
         needle}.

   {Yucca moth} (Zo["o]l.), a small silvery moth ({Pronuba
      yuccasella}) whose larv[ae] feed on plants of the genus
      Yucca.

Source : WordNet®

Yucca aloifolia
     n : a stiff yucca with a short trunk; found in the southern
         United States and tropical America; has rigid
         spine-tipped leaves and clusters of white flowers [syn: {Spanish
         bayonet}]