Musket, any firearm used by infantry in the line of battle during the period 1600–1855.

Musket did not refer to a specific type of arm, but was used successively for matchlock, wheel lock, snaphance, flintlock, and percussion guns. These weapons were usually smoothbores, rather than rifles. When the United States adopted rifles for all troops in 1855, however, the infantry weapon was called a rifle musket, a term used officially until 1873.