A beloved member of the citrus family, the grapefruit was named for the way it clusters on a tree branch — like grapes. It originated in the Caribbean in the early 1800s, and is likely a cross between a pomelo and some other citrus fruit. The main differences between grapefruit and pomelo (also referred to as pummelo or pommelo) are growing locations, color and size.
The pomelo is native to Southeast Asia, is yellow-green in color and ranges from cantaloupe-sized to watermelon-sized, while the grapefruit is grown in semitropical areas of the United States (mainly Florida and Southern California), is a yellow-pink color and is about the size of a fist. In Asian cuisine, the pomelo is often used in sweet jams and jellies, and in dessert soups.