The Collaborative International Dictionary of English v.0.48:

Honeydew melon \Hon"ey*dew` mel"on\, n.
   A type of winter melon (Cucumis melo inodorus) related to
   the muskmelon (Cucumis melo reticulatus), but having a
   smooth pale yellowish-green rind and sweet, juicy, light
   green flesh. It is slightly ovoid in shape, commonly about 8
   to 10 inches long on the long axis.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Muskmelon \Musk"mel`on\, n. [Musk + melon.] (Bot.)
   The fruit of a cucurbitaceous plant (Cucumis Melo) of the
   gourd family, having a peculiar aromatic flavor, and
   cultivated in many varieties, the principal sorts being the
   cantaloupe, of oval form and yellowish flesh, and the smaller
   nutmeg melon with greenish flesh. See Illust. of Melon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Cucumis melo
    n 1: any of several varieties of vine whose fruit has a netted
         rind and edible flesh and a musky smell [syn: sweet
         melon, muskmelon, sweet melon vine, Cucumis melo]