ceratite|ˈsɛrətaɪt| [f.Gr. κέρας, κερατ- horn + -ite.] A fossil Cephalopod, with a discoidal shell having lobed sutures, with the lobes oviculated. 1847Ansted Anc. World vii. 119 Among the cuttle fish..there is a curious example..known as the Ceratite.