1. A firearm which has a long barrel and that is held against a person's shoulder when he or she is shooting it: Hunters around the world use rifles to kill various "wild-game animals" to be used for food or for a so-called "sport".

Brenda's father took his rifle out to go hunting for deer.

2. A BB gun that uses compressed air or gas to fire small pellets: Lucinda's young brother took his air rifle to shoot at some cans lined up on a fence.
3. A weapon that can shoot many bullets quickly and which is designed for use by the military: A unit of soldiers were armed with assault rifles and they were having target practice with these weapons.