The Collaborative International Dictionary of English v.0.48:

Mammee \Mam*mee"\, Mammee tree \Mam*mee" tree`\, n. [Haitian
   mamey.] (Bot.)
   A fruit tree of tropical America, belonging to the genus
   Mammea (Mammea Americana); also, its fruit, called the
   mammee apple. The latter is large, covered with a thick,
   tough ring, and contains a bright yellow pulp of a pleasant
   taste and fragrant scent. It is often called mammee apple.

   Syn: mammee apple, mammee, mamey, Mammea americana.
        [1913 Webster]

WordNet (r) 3.0 (2006):

mammee tree
    n 1: tropical American tree having edible fruit with a leathery
         rind [syn: mammee apple, mammee, mamey, mammee
         tree, Mammea americana]