Raisins are grapes which have been sun dried. Raisins are eaten as snacks and used in cereals and baked goods. You can purchase raisins with seeds or seedless. This dried fruit has a very high sugar content but is a good source of iron, potassium, and calcium.
Prior to medieval Europe, raisins were used as a sweetener along with honey.
Most raisin varieties can be use interchangeably. So for example go ahead and substitute golden raisins for Thompson seedless or muscat raisins for either of those. You can substitute currants (which are just dried Zante grapes) for any other type of raisin but the currants will be sweeter and firmer.
Depending on the recipe, if you want to vary the dried fruit, per 1 cup of raisins needed, substitute 1 cup of: