rai·sin [ ráyz'n ] (plural rai·sins)
dried grape: a sweet grape that has been dried in the sun or by being processed with heat, usually to prevent spoiling and permit long-term storage
[14th century. Via French, "grape" < Latin racemus "bunch, cluster"]
c.1300, from Anglo-Fr. raycin (1278), O.Fr. raisin "grape, raisin," from V.L. *racimus, alteration of L. racemus "cluster of grapes or berries," probably from the same ancient lost Mediterranean language as Gk. rhax (gen. rhagos) "grape, berry."
It is interesting that in English a word that already means grape is relegated to the narrow role of dried grapes.