rein

1 of 2

noun

ˈrān 

1

: a strap fastened to a bit by which a rider or driver controls an animal

—usually used in plural

2

a

: a restraining influence : check

kept a tight rein on the proceedings

b

: controlling or guiding power

—usually used in plural

the reins of government

3

: opportunity for unhampered activity or use

gave full rein to her imagination

Illustration of rein

• R rein 1

rein

2 of 2

verb

reined; reining; reins

transitive verb

1

: to control or direct with or as if with reins

2

: to check or stop by or as if by a pull at the reins

reined in her horse

couldn't rein his impatience

intransitive verb

1

: to stop or slow up one's horse or oneself by or as if by pulling the reins

2

archaic : to submit to the use of reins

Synonyms of rein

Noun

• helm
• chair

Verb

• contain
• regulate
• curb
• control
• keep
• restrain

Examples of rein in a Sentence

Noun

He has people working for him, but he has a tight rein on every part of the process.

after the president resigned, the vice president stepped in and took the reins of the company

Verb

try to rein in your spending, so you have some money left for saving

Recent Examples on the Web

Noun

Some of that is because the technology isn’t fully baked, but some of it is because the end users—whether supply chain operators, store managers or consumers—aren’t ready to hand the reins to an AI model completely. —Meghan Hall, Sourcing Journal, 23 Dec. 2025

Aaron Lacey is taking over the reins of the Livermore-Pleasanton Fire Department, following several months serving as the cities’ interim chief. —Kyle Martin, Mercury News, 22 Dec. 2025

Verb

Now Steve Bannon, one of the populist MAGA movement's architects, has all but declared war on AI, citing economic, political and even religious reasons to rein it in. —Mark Niquette, Arkansas Online, 15 Dec. 2025

Now Steve Bannon, one of the populist MAGA movement’s architects, has all but declared war on AI, citing economic, political and even religious reasons to rein it in. —Mark Niquette, Fortune, 12 Dec. 2025

Word History

Etymology

Noun

Middle English reine, from Anglo-French resne, reine, from Vulgar Latin *retina, from Latin retinēre to restrain — more at retain

First Known Use

Noun

13th century, in the meaning defined at sense 1

Verb

15th century, in the meaning defined at transitive sense 1

Phrases Containing rein

• bearing rein
• free rein
• keep a rein on
• neck-rein
• rein in

Rhymes for rein

• ane
• bane
• blain
• brain
• cane
• chaine
• cheyne
• deign
• drain
• fain
• fane
• feign

Kids Definition

rein

1 of 2 noun

ˈrān 

1

: a line or strap fastened to a bit on each side for controlling an animal (as a horse)

—usually used in plural

2

a

: an influence that slows, limits, or holds back

kept the child under a tight rein

b

: controlling or guiding power

—usually used in plural

seized the reins of government

3

: complete freedom : scope

gave full rein to her imagination

rein

2 of 2 verb

: to check, control, or stop by or as if by reins

reined in the horse

couldn't rein his impatience