1. (Gunnery)
Defn: The diameter of the bore, as a cannon or other firearm, or of any tube; or the weight or size of the projectile which a firearm will carry; as, an 8 inch gun, a 12-pounder, a 44 caliber. The caliber of empty tubes. Reid. A battery composed of three guns of small caliber. Prescott.
Note: The caliber of firearms is expressed in various ways. Cannon are often designated by the weight of a solid spherical shot that will fit the bore; as, a 12-pounder; pieces of ordnance that project shell or hollow shot are designated by the diameter of their bore; as, a 12 inch mortar or a 14 inch shell gun; small arms are designated by hundredths of an inch expressed decimally; as, a rifle of .44 inch caliber.
2. The diameter of round or cylindrical body, as of a bullet or column.
3. Fig.: Capacity or compass of mind. Burke. Caliber compasses. See Calipers. — Caliber rule, a gunner's calipers, an instrument having two scales arranged to determine a ball's weight from its diameter, and conversely. — A ship's caliber, the weight of her armament.
CALIBRATE
Cal"i*brate, v. i.
Defn: To ascertain the caliber of, as of a thermometer tube; also, more generally, to determine or rectify the graduation of, as of the various standards or graduated instruments.
CALIBRATION
Cal`ibra"*tion, n.
Defn: The process of estimating the caliber a tube, as of a thermometer tube, in order to graduate it to a scale of degrees; also, more generally, the determination of the true value of the spaces in any graduated instrument.
CALICE
Cal"ice, n. Etym: [See Calice.]