Source : Webster's Revised Unabridged Dictionary (1913)

Eggplant \Egg"plant`\, n. (Bot.)
   A plant ({Solanum Melongena}), of East Indian origin, allied
   to the tomato, and bearing a large, smooth, edible fruit,
   shaped somewhat like an egg; mad-apple.

Source : WordNet®

Solanum melongena
     n : hairy upright herb native to southeastern Asia but widely
         cultivated for its large glossy edible fruit commonly
         used as a vegetable [syn: {eggplant}, {aubergine}, {brinjal},
          {eggplant bush}, {garden egg}, {mad apple}]