Rein

1. Hence, an instrument or means of curbing, restraining, or governing; government; restraint.
2. The strap of a bridle, fastened to the curb or snaffle on each side, by which the rider or driver governs the horse.
3. To restrain; to control; to check.
4. To govern or direct with the reins; as, to rein a horse one way or another.
5. To be guided by reins.