encephalous,a.Zool.|ɛnˈsɛfələs| [f. Encephal-a + -ous.] Of molluscs: Possessing a distinct head; belonging to the Encephala. 1851Richardson Geol. viii. 229 The encephalous orders possess organs of sense.1875Blake Zool. 243 Encephalous molluscs, with locomotive and prehensile organs.