Assault rifle was a military term for a shorter rifle, shooting a lower-powered shorter-range cartridge than traditional rifles, that is capable of fully-automatic or burst fire operation. This is in contrast to the battle rifle, which is a full-length rifle that fires a full-powered cartridge usually only in semi-auto mode.
The average person cannot buy an assault rifle today. AR-15s and semi-auto AK-47s (technically, a semi-auto version is an AKM) do not meet the military definition of an assault rifle. Instead, they are simply semi-automatic rifles, nothing more.
Since they fire a single shot for every trigger pull, I call them “single shot rifles”...
;>)