Read the dictionary definition of barrel. All definitions for this word.
1. a cylindrical container that holds liquids
2. a tube through which a bullet travels when a gun is fired
3. any of various units of capacity
1. a barrel of beer is 31 gallons and a barrel of oil is 42 gallons
4. the quantity that a barrel (of any size) will hold
5. a bulging cylindrical shape; hollow with flat ends
6. put in barrels