Rein

noun
1.
Often, reins. a leather strap, fastened to each end of the bit of a bridle, by which the rider or driver controls a horse or other animal by pulling so as to exert pressure on the bit.
2.
any of certain other straps or thongs forming part of a harness, as a checkrein.
3.
any means of curbing, controlling, or directing; check; restraint.
4.
reins, the controlling or directing power:
the reins of government.
verb (used with object)
5.
to check or guide (a horse or other animal) by exerting pressure on a bridle bit by means of the reins.
6.
to curb; restrain; control.
verb (used without object)
7.
to obey the reins:
a horse that reins well.
8.
to rein a horse or other animal.
Idioms
9.
draw rein, to curtail one’s speed or progress; halt:
The rider saw the snake and drew rein sharply.
10.
give rein to, to give complete freedom to; indulge freely:
to give rein to one’s imagination.
Also, give free rein to, give full rein to.
plural noun
1.
the kidneys.
2.
the region of the kidneys, or the lower part of the back.
3.
(especially in Biblical use) the seat of the feelings or affections, formerly identified with the kidneys.
noun
1.
(often pl) one of a pair of long straps, usually connected together and made of leather, used to control a horse, running from the side of the bit or the headstall to the hand of the rider, driver, or trainer
2.
a similar device used to control a very young child
3.
any form or means of control: to take up the reins of government
4.
the direction in which a rider turns (in phrases such as on a left (or right) rein, change the rein)
5.
something that restrains, controls, or guides
6.
give free rein, give a free rein, to allow considerable freedom; remove restraints
7.
keep a tight rein on, to control carefully; limit: we have to keep a tight rein on expenditure
8.
on a long rein, with the reins held loosely so that the horse is relatively unconstrained
9.
shorten the reins, to take up the reins so that the distance between hand and bit is lessened, in order that the horse may be more collected
verb
10.
(transitive) to check, restrain, hold back, or halt with or as if with reins
11.
to control or guide (a horse) with a rein or reins: they reined left
plural noun
1.
(archaic) the kidneys or loins

reins (rānz)
pl.n.
The kidneys, loins, or lower back.

the kidneys, the supposed seat of the desires and affections; used metaphorically for “heart.” The “reins” and the “heart” are often mentioned together, as denoting the whole moral constitution of man (Ps. 7:9; 16:7; 26:2; 139:13; Jer. 17:10, etc.).