sunflower Syllabification: (sun·flow·er)Pronunciation: /ˈsənˌflou(-ə)r/Translate sunflower | into French | into German | into Italian | into Spanish Definition of sunflower noun a tall North American plant of the daisy family, with very large golden-rayed flowers. Sunflowers are cultivated for their edible seeds, which are an important source of oil for cooking and margarine. Helianthus annus, family Compositae sunflower in other Oxford dictionaries Definition of sunflower in the British & World English dictionary