is a specific kind of: fruit tree.

is a broader term that covers: Annona cherimola, cherimoya, cherimoya tree | Annona diversifolia, ilama, ilama tree | Annona muricata, prickly custard apple, soursop, soursop tree | Annona reticulata, bullock's heart, bullock's heart tree, bullock heart | Annona squamosa, sweetsop, sweetsop tree | Annona glabra, pond-apple tree, pond apple | Asimina triloba, papaw, papaw tree, pawpaw.

has as a part: custard apple.

is a member of: Annona, genus Annona.