"Semi-automatics shoot one bullet per trigger pull -- that's the definition."
In the interest of accuracy Ann: A semi-automatic weapon is one that automatically reloads the firing chamber after having been being fired, but requires that the trigger be pulled to discharge the next round. A musket will not reload.
The press have perverted the meaning of the term "Assault weapon." The military definition of an assault weapon was a fully rifle capable of fully automatic fire, which chambered a mid sized cartridge, something less than, say, a .308 or .30-06. Examples of the differences are the 7.62X39 MM which is for an assault rifle and a 7.62X54 MM which is for a longer range weapon.