honeydew melon

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A variety of melon (Cucumis melo) having a smooth whitish rind and sweet green flesh.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a melon with sweet green flesh and a smooth greenish-white rind.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the fruit of a variety of winter melon vine; a large smooth greenish-white melon with pale green flesh
• noun 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