The Collaborative International Dictionary of English v.0.48:

Sechium \Se"chi*um\, n. [NL.: cf. F. s['e]chion; perhaps formed
   fr. Gr. ? cucumber.] (Bot.)
   The edible fruit of a West Indian plant (Sechium edule) of
   the Gourd family. It is soft, pear-shaped, and about four
   inches long, and contains a single large seed. The root of
   the plant resembles a yam, and is used for food.
   [1913 Webster]