1) Originally a withe or withy, that is a tough, flexible but slender branch of a willow or osier, used as a tie or shackle, presumably attached to the ‘tug’ on a working horse. It was later applied to an iron chain which had the same function.
1551 a ploughe foote shakill, a tugwithe and a plewbyeme, Altofts
1559 too iron tugwythes, Castleford
1613 a harrow, freat & a tugwythye of iron, Cottingley
1675 2 iron sugwidies [sic], Selby.