cal�i�ber (kl-br)
n.
1. Abbr. cal.
a. The diameter of the inside of a round cylinder, such as a tube.
b. The diameter of the bore of a firearm, usually shown in hundredths or thousandths of an inch and expressed in writing or print in terms of a decimal fraction: .45 caliber.
c. The diameter of a large projectile, such as an artillery shell, measured in millimeters or in inches.
