The Collaborative International Dictionary
pompelmous
Shaddock \Shad"dock\, n. [Said to be so called from a Captain Shaddock, who first brought this fruit from the East Indies.] (Bot.) A tree ( Citrus decumana) and its fruit, which is a large species of orange; -- called also forbidden fruit, and pompelmous.
Wiktionary
pompelmous
n. (context obsolete English) A grapefruit.