1. the internal diameter of a gun barrel or the diameter of a bullet or shell
Usage: firearms
2. degree of merit or excellence; quality

Examples

• The rifle fires bullets of different calibers.
• Police found shell casings of various calibers at the scene.
• We need employees of the highest caliber for this project.
• The team recruited players of exceptional caliber.
• Her work is of a caliber that deserves recognition.
• The company only hires candidates of proven caliber.