Citrus fruit includes, among others, grapefruit. It’s obviously called a “grapefruit” because of how much it resembles a grape, right? Or maybe not…
The grapefruit is relatively recent, as fruits go. It evidently showed up in Barbados in the 1700s as a naturally-occurring cross between oranges and a lesser-known fruit today called a “pomelo.” The pomelo is also called a “shaddock,” thanks to the British East India company bringing some to England in the late 1700s — the captain of the ship that first brought the fruit was Captain Shaddock.
But the origin of the name “grapefruit” isn’t based on a Captain Grape, although that would have probably made a better story. The first person to describe it (not as a “grapefruit”) in English was the Reverend Griffith Hughes, in 1750. Possibly because he was a minister, the grapefruit acquired a quasi-religious association right away; for a long time it was called the “forbidden fruit” because people thought — since they’d never seen it before — that it might be that original fruit from the Garden of Eden. It’s not clear whether the Reverend Hughes started this rumor, though.
There was in 1814 a book called “Hortus Jamaicencis,” written by John Lunan, that catalogued the plants found in Jamaica. Lunan was the first to use the word “grapefruit” in print, and explained that: “There is a variety known by the name of grape-fruit, on account of its resemblance in flavour to the grape; this fruit is not near so large as the shaddock.”
From his description, it’s pretty clear that either Lunan had never actually tasted a grapefruit, or grapefruit in those days tasted a lot different. That’s actually possible, because he also describes it as smaller than a shaddock, or pumelo. Today a grapefruit is about the same size as a pumelo — but because of its popularity, grapefruit has been raised commercially for a long time, and the ones we’re familiar with today are the product of decades of careful cultivation and hybridization.
Not only that, but Lunan was mistaken in the first place about where the name “grapefruit” came from. It had nothing to do with taste. Small, unripe grapefruit grow in bunches that resemble bunches of grapes.