adjective: (chiefly science fiction) Of Earth; of terrestrial origin.
noun: (chiefly science fiction) An inhabitant of Earth; an earthling, especially a human.
noun: A hypothetical language spoken throughout all of Earth.
adjective: (chiefly science fiction, uncommon) Alternative letter-case form of Terran (“of or from Earth; terrestrial”) [(chiefly science fiction) Of Earth; of terrestrial origin.]