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. Sometimes applied to a similar cylindrical container made of metal, usually called a drum.

"a cracker barrel"

The quantity which constitutes a full barrel: the volume or weight this represents varies by local law and custom.

A solid drum, or a hollow cylinder or case

"the barrel of a windlass;  the barrel of a watch, within which the spring is coiled."

A metallic tube, as of a gun, from which a projectile is discharged.

A tube.

The hollow basal part of a feather.

The part of a clarinet which connects the mouthpiece and upper joint, and looks rather like a barrel (1).

A wave that breaks with a hollow compartment.

A waste receptacle.

"Throw it into the trash barrel."

The ribs and belly of a horse or pony.

A jar.

Any of the dark-staining regions in the somatosensory cortex of rodents, etc., where somatosensory inputs from the contralateral side of the body come in from the thalamus.

A statistic derived from launch angle and exit velocity of a ball hit in play.

To put or to pack in a barrel or barrels.

To move quickly or in an uncontrolled manner.

"He came barrelling around the corner and I almost hit him."