A knife that can be fixed to the end of a rifle and used as a weapon WordNet 3.0 & Open English WordNet

A bayonet is a knife, dagger, sword, or spike-shaped weapon designed to fit on the end of the muzzle of a rifle, carbine, musket or similar firearm, allowing it to be used as a spear-like weapon. Wikipedia

Blade fastened to the end of a gun or rifle. Wikipedia Disambiguation

Bladed weapon designed for attachment to a firearm Wikidata

A pointed instrument of the dagger kind fitted on the muzzle of a musket or rifle, so as to give the soldier increased means of offence and defence. OmegaWiki

A pointed instrument of the dagger kind fitted on the muzzle of a musket or rifle, so as to give the soldier increased means of offence and defence. Originally, the bayonet was made with a handle, which needed to be fitted into the bore of the musket after the soldier had fired. Wiktionary