1.  The usually round, red or yellow, edible fruit of a small tree, Malus sylvestris,  of the rose family.
2.  The tree, cultivated in most temperate regions.
3.  The fruit of any of certain other species of tree of the same genus.
4.  Any of these trees.
5.  Any of various other similar fruits, or fruitlike products or plants, as the custard apple, love apple, May apple, or oak apple.