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®

bear grass
     n 1: yucca of southern United States having a clump of basal
          grasslike leaves and a central stalk with a terminal
          raceme of small whitish flowers [syn: {Yucca smalliana}]
     2: yucca of west central United States having a clump of basal
        grasslike leaves and a central stalk with a terminal
        raceme of small whitish flowers [syn: {Yucca glauca}]
     3: stemless plant with tufts of grasslike leaves and erect
        panicle of minute creamy white flowers; southwestern
        United States and Mexico [syn: {Nolina microcarpa}]
     4: plant of western North America having woody rhizomes and
        tufts of stiff grasslike basal leaves and spikes of creamy
        white flowers [syn: {squaw grass}, {Xerophyllum tenax}]