grapefruit (n.)

1814, from grape + fruit. Said to have been so called for its taste, or perhaps because it grows in clusters. Perhaps a marketing name; it was known by various names (pomelo, shaddock) before the current one emerged. The fruit itself was known since 1693 (in Hans Sloane's catalogue of Jamaican plants); presumably it originated in Jamaica from chance hybrids between other cultivated citrus. An ornamental plant chiefly at first, not much eaten until late 19c.