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rein

2 ENTRIES FOUND:
1 rein /ˈreɪn/ noun
plural reins
1 rein
/ˈreɪn/
noun
plural reins
Britannica Dictionary definition of REIN
[count]
: a strap that is fastened to a device (called a bridle) placed on the head of an animal (such as a horse) and that is used to guide and control the animal usually plural see picture at horse
: the ability to limit or control something
: the power to guide or control someone or something usually plural

free/full rein

: the opportunity to act freely
2 rein /ˈreɪn/ verb
reins; reined; reining
2 rein
/ˈreɪn/
verb
reins; reined; reining
Britannica Dictionary definition of REIN

rein in

[phrasal verb]
rein (someone or something) in or rein in (someone or something)
: to limit or control (someone or something)
: to make (an animal) stop by using reins