1(of a species, family, or other larger group) having no living members:trilobites and dinosaurs are extinct no longer in existence:an extinct language the sort of girls' school that is now extinct (of a title of nobility) having no valid claimant: the baronetcy became extinct
2(of a volcano) not having erupted in recorded history: the islands are the remains of extinct volcanoes no longer alight:his now extinct pipe
