I’ve never understood the term assault rifle. Most assaults are done with fists, blunt object and maybe a knife. Guns are for killing things.
It started out as a *military* designation for a rifle that is suited (due to lighter weight, compact length, etc.) to forces tasked with rapidly and aggressively engaging enemy positions. Later, the military definition would grow to add certain characteristics (select-fire capability, intermediate cartridge size). Initially, though, it was a translation of what the Germans called their first such firearm: sturmgewehr. Sturm = Storm, as in "Have fun storming the castle!" Yes, the military uses the word "assault" a bit differently than the state laws do.