muzzleloader Syllabification: (muz·zle·load·er)Pronunciation: /ˈməzəlˌlōdər/Definition of muzzleloader noun historical a gun that is loaded through its muzzle. Derivatives muzzleloadingPronunciation: /-ˌlōdiNG/ (also muzzle-loading) adjective muzzleloader in other Oxford dictionaries Definition of muzzleloader in the British & World English dictionary