Definition of "caliber" []

• The diameter of the inside of a round cylinder, such as a tube. (noun)
• 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. (noun)
• The diameter of a large projectile, such as an artillery shell, measured in millimeters or in inches. (noun)
• Degree of worth; quality: a school of high caliber; an executive of low caliber. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The word caliber is not used when giving the metric measurement."
• "In my opinion the caliber is at its best when shots present themselves at 100 yards or more, although I have killed several dear at less than 50 with it."
• "I have no problem with someone using a military style rifle to hunt with provided the caliber is adequate for the job at hand."