caliber

plural calibers · alternative calibre

1. UScountableuncountableDiameter of the bore of a firearm, typically measured between opposite lands.
2. UScountableuncountableThe diameter of round or cylindrical body, as of a bullet, a projectile, or a column.
3. UScountableuncountableA nominal name for a cartridge type, which may not exactly indicate its true size and may include other measurements such as cartridge length or black powder capacity. Eg 7.62×39 or 38.40.
4. UScountableuncountableUnit 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.
5. UScountablefigurativelyuncountableRelative size, importance, magnitude.

   A snort of about the calibre of an explosion in an ammunition dump escaped my late father's sister.

   1960, P[elham] G[renville] Wodehouse, chapter XIII, in Jeeves in the Offing, London: Herbert Jenkins, →OCLC

6. UScountablefigurativelyuncountableCapacity or compass of mind.
7. UScountabledateduncountableDegree of importance or station in society.
8. UScountableuncountablehobbiesMovement of a timepiece.