kerogen Syllabification: (ker·o·gen)Pronunciation: /ˈkerəjən/Definition of kerogen noun a complex fossilized organic material, found in oil shale and other sedimentary rock, that is insoluble in common organic solvents and yields petroleum products on distillation. Origin: early 20th century: from Greek kēros 'wax' + -genkerogen in other Oxford dictionaries Definition of kerogen in the British & World English dictionary