n.1. The forward, projecting part of the head of certain animals, such as dogs, including the mouth, nose, and jaws; the snout.
2. A device that is fitted over an animal's snout, often used to prevent biting or eating.
3. The forward, discharging end of the barrel of a firearm.
4. A restraint on free movement or expression: had a muzzle put on their high spirits.