My understanding was that there is already a clear definition of the term and that there was actually already an assault weapons ban too?
Yes. One that classified weapons based on aesthetic features and was utterly meaningless.
We had an assault weapons ban, the legal definition is already established.
See above.
If people are seriously suggesting reinstating the 1994 legislation as something that will be useful you should really read about what it was, and the utter lack of usefulness of it.
Edit: Actually, Ishould probably take a leaf from my own book and provide some information
The 1994 AWB banned the following:
Semi-automatic rifles able to accept detachable magazines and two or more of the following:
Folding or telescoping stock
Pistol grip
Bayonet mount
Flash suppressor, or threaded barrel designed to accommodate one
Grenade launcher (more precisely, a muzzle device that enables launching or firing rifle grenades, though this applies only to muzzle mounted grenade launchers and not those mounted externally).
Semi-automatic pistols with detachable magazines and two or more of the following:
Magazine that attaches outside the pistol grip
Threaded barrel to attach barrel extender, flash suppressor, handgrip, or suppressor
Barrel shroud that can be used as a hand-hold
Unloaded weight of 50 oz (1.4 kg) or more
A semi-automatic version of a fully automatic firearm.
Semi-automatic shotguns with two or more of the following:
Folding or telescoping stock
Pistol grip
Fixed capacity of more than 5 rounds
Detachable magazine.
Now, much of that has zero functional bearing on the ability of the weapon to kill people quickly, and also creates a false sense that something has been done to help prevent future attacks when that is not the case. It is not only useless, it is worse than useless.