Etymology

From Middle English thurrok, from Old English þurruc ‎(“a small boat, the hold of a ship, drain”), from Proto-Germanic *þurrukaz, *þurką, *þirką ‎(“groundwater in a ship, hole”), from Proto-Indo-European *terg-, *terǵ- ‎(“to rub, wipe, clean, make holes”). Cognate with Saterland Frisian durk ‎(“sewer, bilge-water, lowest part in the hold of a ship”), Middle Dutch durck, dorck ‎(“the hold of a ship”) (Dutch durk, dork ‎(“a spout-hole”)), Middle Low German dork ‎(“keel room, the lowest part of a ship's hold”), Gothic 𐌸𐌰𐌹𐍂𐌺𐍉 ‎(þairkō, “hole, eye (of a needle)”), Latin tergō, tergeō ‎(“wipe, scour, clean”, verb), Old English þurh, þuruh ‎(“through”). More at through, thorough.