watermelon

from WordNet (r) 3.0 (2006)

watermelon
    n 1: an African melon [syn: {watermelon}, {watermelon vine},
         {Citrullus vulgaris}]
    2: large oblong or roundish melon with a hard green rind and
       sweet watery red or occasionally yellowish pulp

from The Collaborative International Dictionary of English v.0.48

Watermelon \Wa"ter*mel`on\, n. (Bot.)
   The very large ovoid or roundish fruit of a cucurbitaceous
   plant ({Citrullus vulgaris}) of many varieties; also, the
   plant itself. The fruit sometimes weighs many pounds; its
   pulp is usually pink in color, and full of a sweet watery
   juice. It is a native of tropical Africa, but is now
   cultivated in many countries. See Illust. of {Melon}.
   [1913 Webster]