Terret

A terret is a metal loop on horse harness, guiding the lines and preventing them from becoming tangled or snagged on the harness.

The lines run from the hands of the driver, through the terrets, and then attach to the horse's bit to guide the horse. Most harness has two pairs of terrets, one on the harness saddle, and one on the hames of the collar (or on the neck-strap of a breast collar). Terrets are commonly made of brass or steel, and they may stand up stiffly, or they may consist of a hinged ring. They are usually circular, but may be U-shaped or square.