honeydew melon

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A kind of melon (Cucumis melo) having a smooth whitish rind and green flesh. Also called winter melon.

Wiktionary

1. n. a melon with sweet green flesh and a smooth greenish-white rind.

GNU Webster's 1913

1. 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.

WordNet 3.0

1. n. the fruit of a variety of winter melon vine; a large smooth greenish-white melon with pale green flesh
2. n. any of a variety of muskmelon vines having fruit with a smooth white rind and white or greenish flesh that does not have a musky smell