Source : Webster's Revised Unabridged Dictionary (1913)

Lemonade \Lem`on*ade"\ (l[e^]m`[u^]n*[=a]d"), n. [F. limonade;
   cf. Sp. limonada, It. limonata. See {Lemon}.]
   A beverage consisting of lemon juice mixed with water and
   sweetened.

Source : WordNet®

lemonade
     n : sweetened beverage of diluted lemon juice