The Collaborative International Dictionary of English v.0.48:

Honeydew \Hon"ey*dew`\, n.
   1. A sweet, saccharine substance, found on the leaves of
      trees and other plants in small drops, like dew. Two
      substances have been called by this name; one exuded from
      the plants, and the other secreted by certain insects,
      esp. aphids.
      [1913 Webster]

   2. A kind of tobacco moistened with molasses.
      [1913 Webster]

   3. A honeydew melon.
      [PJC]

WordNet (r) 3.0 (2006):

honeydew
    n 1: the fruit of a variety of winter melon vine; a large smooth
         greenish-white melon with pale green flesh [syn:
         honeydew, honeydew melon]