caliber, calipers Excluding an isolated and semantically unclear record in northern France in 1478, the early records are in French in the early and mid 16th century spelled calibre, equally often spelled qualibre, with two concurrent meanings: (1) "the interior diameter of a gun-barrel" and (2) "the quality or comparative character of anything". The source-word for the French is uncertain. A popular idea is that it came from Arabic قالب qālib = "mold" but evidence to support this idea is very scant.[37]