postorbital Syllabification: (post·or·bit·al)Pronunciation: /pōstˈôrbətl/ chiefly ZoologyDefinition of postorbital adjective [attributive] situated at the back of the orbit or eye socket, in particular denoting a process of the frontal bone that in some reptiles forms a separate bone. noun a postorbital bone. postorbital in other Oxford dictionaries Definition of postorbital in the British & World English dictionary