We don't have synonyms for terrans yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are terrane, terran and terras.
(n) :
(chiefly science fiction) An inhabitant of Earth; an earthling, especially a human.
(adj) :
(chiefly science fiction) Of Earth; of terrestrial origin.
(n) :
A hypothetical language spoken throughout all of Earth.
(adj) :
(chiefly science fiction, uncommon) Alternative letter-case form of Terran (“of or from Earth; terrestrial”). [(chiefly science fiction) Of Earth; of terrestrial origin.]
(n) :
(chiefly science fiction) An inhabitant of Earth; an earthling, especially a human.
(adj) :
(chiefly science fiction) Of Earth; of terrestrial origin.
(n) :
A hypothetical language spoken throughout all of Earth.
(adj) :
(chiefly science fiction, uncommon) Alternative letter-case form of Terran (“of or from Earth; terrestrial”). [(chiefly science fiction) Of Earth; of terrestrial origin.]