The Collaborative International Dictionary of English v.0.48:

Cucumis \Cu"cu*mis\ (k?k?--m?s), n. [L., cucumber.] (Bot.)
   A genus of plants including the cucumber, melon, and same
   kinds of gourds.
   [1913 Webster] Cucurbit

WordNet (r) 3.0 (2006):

Cucumis
    n 1: cucumbers; muskmelons [syn: Cucumis, genus Cucumis]