Caliber
Part of speech: noun
Definition: Diameter of the bore of a firearm, typically measured between opposite lands.
Calibre
Part of speech: noun
Definition: Diameter of the bore of a firearm. In rifled firearm barrels the calibre is obtained by measuring between opposite lands. A calibre 0.45 revolver has a barrel with a land diameter 45/100 of an inch. The metric equivalent is 11.43 millimeters.The diameter of round or cylindrical body, as of a bullet, a projectile, or a column.Unit of measure used to express the length of the bore of a weapon. The number of calibres is determined by dividing the length of the bore of the weapon, from the breech face of the tube to the muzzle, by the diameter of its bore. A gun tube the bore of which is 40 feet (480 inches) long and 12 inches in diameter is said to be 40 calibers long.Capacity or compass of mind.Degree of importance or station in society.