Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
.45-calibre is an adjective meaning "of or relating to the bore of a gun (or its ammunition) that measures forty-five hundredths of an inch in diameter". It carries one recorded sense.
of or relating to the bore of a gun (or its ammunition) that measures forty-five hundredths of an inch in diameter
Definitions, synonyms and semantic relations for .45-calibre come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.