Raisin n. : A grape, or a bunch of grapes.

Raisin n. : A grape dried in the sun or by artificial heat.

Example:
Can I make oatmeal Raisin cookies without baking soda?

Taxonomy
Raisin, grape, sugars, free encyclopedia, varieties, Old French, Nutritional value, Sultana, raisin sec, dried grape, flame, Grape and raisin toxicity in dogs, Sultana Raisins, Etymology, bunch of grapes, seedless grape, dried fruits, natural sugar.

Defination from the web:
Raisins are dried grapes. ... Golden raisins" are made from Sultanas, treated with Sulfur Dioxide (SO2) , and flame dried to give them ... In the United Kingdom, Ireland, Australia and New Zealand, the word raisin is reserved for the dried large dark grape, with sultana being a dried ...