Where does “tra-” come from?
tra- (Esperanto) comes from Esperanto tra, from Latin trāns, from Latin Padus, from Lepontic Bodincus, from Proto-Indo-European bʰudʰmḗn, from Proto-Indo-European dʰewbʰ-, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.
Ancestry of “tra-”, step by step