The muzzle of an animal such as a dog is its nose and mouth.

A muzzle is an object that is put over a dog's nose and mouth so that it cannot bite people or make a noise.

If you muzzle a dog or other animal, you put a muzzle over its nose and mouth.

If you say that someone is muzzled, you are complaining that they are prevented from expressing their views freely.

The muzzle of a gun is the end where the bullets come out when it is fired.