The Collaborative International Dictionary of English v.0.48:

Pepo \Pe"po\ (p[=e]"p[-o]), n. [L., a kind of melon, from Gr.
   pe`pwn.] (Bot.)
   Any fleshy fruit with a firm rind, as a pumpkin, melon, or
   gourd. See Gourd.
   [1913 Webster]