xanthophyllEnglishOxford New American Dictionaryxanthophyll /ˈzanTHəˌfil, ˈzænθəˌfɪl / ▸ noun Biochemistry a yellow or brown carotenoid plant pigment which causes the autumn colors of leaves. – ORIGIN mid 19th century : from Greek xanthos ‘yellow’ + phullon ‘leaf’.