From Proto-Italic *trānts, from Proto-Indo-European *tr̥h₂-n̥ts, from *terh₂- (“through, throughout, over”). Cognate with English through, Scots throch (“through”), West Frisian troch (“through”), Dutch door (“through”), German durch (“through”), Gothic 𐌸𐌰𐌹𐍂𐌷 (þairh, “through”), Albanian tërthor (“through, around”), Welsh tra (“through”). See also thorough. The accusative is from the pre-PIE directional. Compare Sanskrit तिरस् (tiras).