As to the definition of “weapon”, it includes things that are simply used as a weapon. It need not be originally a weapon but simply used as a weapon.
If I understand the question correctly, it focuses on—I'll just use the English term, if you don't mind—an “imitation firearm”. If that's the question, I can also add that “imitation firearm” is defined in section 84 of the Criminal Code. It's quite a simplistic definition. It's just anything that imitates a firearm.