Grapefruit Definition

Origin of Grapefruit

• From grape +‎ fruit, an allusion to the grapelike clusters of fruit on the tree. Ciardi proposes another theory. The pummelo's botanical name was Citrus grandis, meaning "great citrus [fruit]", due to the large size of the fruits. It would be natural to call the new pummelo variety a "greatfruit". By saying that name a few times, with its consonant cluster, it sounds like "grapefruit", and it would easily have morphed to that form. This second suggestion is completely speculative, without attestation, but seems much more reasonable than the equally speculative "grape cluster" theory. Actually, pummelo fruits do not not grow in grapelike clusters.

  From Wiktionary

• Probably so called because the fruit grows in clusters

  From American Heritage Dictionary of the English Language, 5th Edition