The custard-apple, also called bullock's heart or bull's heart, is the fruit of the tree Annona reticulata. This tree is a small deciduous or semi-evergreen tree sometimes reaching 10 metres (33 ft) tall and a native of the tropical New World that prefers low elevations, and a warm, humid climate. It also occurs as feral populations in many parts of the world including Southeast Asia, Taiwan, India, Australia, and Africa.
The fruits are variable in shape, heart shaped, oblong or irregular. The size ranges from 7 centimetres (2.8 in) to 12 centimetres (4.7 in). When ripe, the fruit is brown or yellowish, with red highlights and a varying degree of reticulation, depending on variety. The flavour is sweet and pleasant.
In some regions of the world, "custard-apple" is another name for sugar-apple or sweetsop (Annona squamosa), a different plant in the same genus. In Britain, "custard-apple" refers to cherimoya, the fruit of Annona cherimola, a third plant in the same genus.