muzzle

: the usually long nose and mouth of an animal (such as a dog, horse, or pig) : snout — see picture at horse

: a covering for the mouth of a dog that stops it from biting people

: the hole at the end of a gun where the bullet comes out — see picture at gun

: to put a muzzle on (a dog) : to place a covering on (the mouth of a dog) to stop biting

: to prevent (a person or group) from speaking or writing in a free or normal way