Other forms: grapefruits
A grapefruit is a large citrus fruit that grows on a tree. Ripe grapefruits are very slightly sour, juicy, and delicious.
The first grapefruits were an accident — they came from an inadvertent cross between an orange and a pomelo. Both of those species are native to Asia, but the grapefruit's accidental invention happened in Barbados some time in the 18th century. The name comes from the way the fruit clusters on the tree, close together like grapes, rather than its taste, which is a mixture of sweetness and acidity.