watermelonPronunciation: /ˈwɔːtəmɛlən/Translate watermelon | into French | into German | into Italian | into Spanish Definition of watermelon noun 1the large melon-like fruit of a plant of the gourd family, with smooth green skin, red pulp, and watery juice. 2the African plant which yields watermelons. Citrullus lanatus, family Cucurbitaceae watermelon in other Oxford dictionaries Definition of watermelon in the US English dictionary