The grapefruit gets its name from the way it grows in clusters like grapes on a vine.
It is believed that the name refers to how grapefruit grows in clusters on a tree. Most botanists agree that the grapefruit is a cross between a pummelo External link and a sweet orange External link. Grapefruit, like all citrus fruit, is a Hesperidum, or a large modified berry with a thick rind.
If you see grapefruit growing on a tree, you will notice that they grow in clusters. It is suggested that these clusters resemble the shape of large yellow grapes and so the fruit was called a grapefruit. Another explanation is that the premature grapefruit looks similar in shape to unripe green grapes.