Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.
See caliber, def. 1.
calibreThe diameter of a tube or cylinder.
The diameter of a bullet measured in hundredths of an inch—in the US and in English-speaking countries.
Common bullet calibres .22, .25, .30, .32, .38, and .45; in metric countries, calibres are measured in millimetres—e.g., .38 calibre corresponds to 9 mm