rein

verb3

1. •
   To direct or stop a horse by using reins.

   • He mounts and reins his horse. — 1611
2. •
   To restrain; to control; to check.

   • Being once chafed, he cannot / Be reined again to temperance. — 1608
3. •
   To obey directions given with the reins.

   • She worked each horse at a walk, trot, and then a canter. The horses reined well and executed stops quickly. — 2011

noun4

1. •
   A strap or rope attached to a bridle or bit, used to control a horse, other animal or young child.
2. •
   (figurative) An instrument or means of curbing, restraining, or governing.

   • The government is attempting to keep a rein on rising prices.
3. •
   The inward impulses; the affections and passions, formerly supposed to be located in the area of the kidneys.

   • My reins rejoice, when thy lips speak right things. — 1611
4. •
   (no longer used) A kidney.

   • a man subject to these like imaginations[…]hath often the stone imaginarily, before he have it in his reines[…]. — 1603

noun1

1. •
   Acronym of repetitive electrical impulse noise.