A sweet apple is an apple that is bred to be sweet enough to eat out of hand, or to be used to contribute sugar to cider. The term dessert apple or table apple is used for apples that are specifically intended to be eaten raw as dessert fruits, but many sweet cider apples are also sweet enough to eat out of hand.
Sweet is also a classification under the Long Ashton apple classification scheme used for cider making for apples with low acidity and low tannin content (which may not actually have higher sugar levels). Contrast sharp, bittersharp, and bittersweet.