jackfruitPronunciation: /ˈdʒakfruːt/Definition of jackfruit noun a fast-growing tropical Asian tree related to the breadfruit. Artocarpus heterophyllus, family Moraceae the very large edible fruit of the jackfruit tree, resembling a breadfruit and important as food in the tropics. Origin: late 16th century: from Portuguese jaca (from Malayalam chakka) + fruitjackfruit in other Oxford dictionaries Definition of jackfruit in the US English dictionary