The Collaborative International Dictionary of English v.0.48:

Calabash \Cal"a*bash\ (k[a^]l"[.a]*b[a^]sh), n. [Sp. calabaza,
   or Pg. calaba[,c]a, caba[,c]a (cf. F. Calebasse), lit., a dry
   gourd, fr. Ar. qar', fem., a kind of gourd + aibas dry.]
   1. The common gourd (plant or fruit).
      [1913 Webster]

   2. The fruit of the calabash tree.
      [1913 Webster]

   3. A water dipper, bottle, bascket, or other utensil, made
      from the dry shell of a calabash or gourd.
      [1913 Webster]

   Calabash tree. (Bot.), a tree of tropical America
      (Crescentia cujete), producing a large gourdlike fruit,
      containing a purgative pulp. Its hard shell, after the
      removal of the pulp, is used for cups, bottles, etc. The
      African calabash tree is the baobab.
      [1913 Webster]

WordNet (r) 3.0 (2006):

calabash tree
    n 1: tropical American evergreen that produces large round
         gourds [syn: calabash, calabash tree, Crescentia
         cujete]