Citron

n.
  1. (Bot) A fruit resembling a lemon, but larger, and pleasantly aromatic; it is produced by the citron tree (Citrus medica). The thick rind, when candied, is the citron of commerce. The fruit was once called the lime.
  2. A citron tree, Citrus medica.
  3. A citron melon.
    4. Citron melon
    1. A small variety of muskmelon with sugary greenish flesh.
    2. A small variety of watermelon, whose solid white flesh is used in making sweetmeats and preserves.
    Citron tree (Bot.),
    the tree which bears citrons. It was probably a native of northern India, and is now understood to be the typical form of Citrus Medica.