Where does “Transylvanian” come from?

Transylvanian comes from English Transylvania, from Latin Transylvānia, from Latin -ia, from Ancient Greek -ία, from Latin -ānus, from Proto-Indo-European terh₂- meaning "to cross or pass through," with Latin -us and Proto-Italic -os forming the agent noun.

Transylvanian (English): From, or pertaining to, Transylvania or its...