The grapefruit is so named because it grows in bunches which, when the fruit is unripe, vaguely resemble bunches of grapes. Because of this misleading name, there have been several attempts to rename the fruit.
The grapefruit was first discovered in Jamaica in the 1700s. The fruit was initially thought to be a variant of the pummelo, a giant citrus fruit. In the 1750s, it was often referred to as the "forbidden fruit," in reference to the fruit tree from the Garden of Eden. It also was sometimes called the "smaller shaddock," as the large pummelo was sometimes called a shaddock. Sometime in the early 1800s, a horticulturalist noted the fruit's resemblance to grapes when growing and created its current English moniker.
Although the grapefruit is related to the pummelo, it is not merely a variant. Instead, grapefruit is a hybrid of pummelos and oranges. However, uncovering the true origin of the fruit has not led to a consensus on its naming. The Dutch use either the name "shaddock" or "pampelmoose "to refer to a grapefruit, and France and Italy use terms related to "pampelmoose." In English, the name "grapefruit" remains despite several attempts at rebranding. For example, in 1962, Florida Citrus Mutual pushed to change the name to something more appealing. However, public outcry ended their attempts to rename the grapefruit.