Of or relating to the geographic area under a given jurisdiction: the territorial limits of a country. Relating or restricted to a particular territory; regional: a territorial court. Of or relating to an administrative territory: the territorial government of the U.S. Virgin Islands; Whitehorse, the territorial capital of the Yukon. Organized for national or home defense: the British Territorial Army. Biology Displaying territoriality; defending a territory from intruders: territorial behavior; a territorial species. A member of a territorial army.