1. A container having a circular lateral cross section that is largest in the middle, and ends that are flat; often made of staves held together by hoops.

2. A piece of small pipe inserted in the end of a cartridge to carry the squib to the powder.

3. That portion of a pipe having a constant bore and wall thickness.

1. Abbreviated bbl.

2. The unit of liquid volume equal to 31.5 gallons (approximately 119 liters).

3. The unit of liquid volume for petroleum equal to 42 gallons (approximately 158 liters).

4. The unit of dry volume equal to 105 quarts (approximately 116 liters).

5. A unit of weight that varies in size according to the commodity being weighed.

The central part of a windlass or capstan about which the cable is wound.

A tapering cylindrical housing which contains the lenses of a camera and the iris diaphragm.

The cylindrical metallic part of a gun which controls the initial direction of a projectile.