lacertilian Syllabification: (lac·er·til·i·an)Pronunciation: /ˌlasərˈtilēən, -ˈtilyən/ ZoologyDefinition of lacertilian noun a reptile of the suborder Lacertilia; a lizard. adjective relating to or denoting lacertilians. lacertilian in other Oxford dictionaries Definition of lacertilian in the British & World English dictionary