barreln.[OE. barel, F. baril, prob. fr. barre bar. Cf. Barricade.]1. A round vessel or cask, of greater length than breadth, and bulging in the middle, made of staves bound with hoops, and having flat ends or heads; as, a cracker barrel. Sometimes applied to a similar cylindrical container made of metal, usually called a drum.()2. The quantity which constitutes a full barrel. This varies for different articles and also in different places for the same article, being regulated by custom or by law. A barrel of wine is 311/2 gallons; a barrel of flour is 196 pounds.()3. A solid drum, or a hollow cylinder or case; as, the barrel of a windlass; the barrel of a watch, within which the spring is coiled.()()4. A metallic tube, as of a gun, from which a projectile is discharged.(Knight.)5. A jar.(1 Kings xvii. 12.)6. (Zol.) The hollow basal part of a feather.()Barrel bulk (Com.), a measure equal to five cubic feet, used in estimating capacity, as of a vessel for freight. -- Barrel drain (Arch.), a drain in the form of a cylindrical tube. -- Barrel of a boiler, the cylindrical part of a boiler, containing the flues. -- Barrel of the ear (Anat.), the tympanum, or tympanic cavity. -- Barrel organ, an instrument for producing music by the action of a revolving cylinder. -- Barrel vault. See under Vault.()v. t. To put or to pack in a barrel or barrels.()