Pronunciation: (kal'u-bur), [key]
1. the diameter of something of circular section, esp. that of the inside of a tube: a pipe of three-inch caliber.
2. Ordn.the diameter of the bore of a gun taken as a unit of measurement.
3. degree of capacity or competence; ability: a mathematician of high caliber.
4. degree of merit or excellence; quality: the high moral caliber of the era. Also, esp. Brit.,cal'i•bre.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.