(a) Definition.--Notwithstanding the definition of “weapon” in section 907 (relating to possessing instruments of crime), “weapon” for purposes of this section shall include but not be limited to any knife, cutting instrument, cutting tool, nun-chuck stick, firearm, shotgun, rifle and any other tool, instrument or implement capable of inflicting serious bodily injury.

(b) Offense defined.--A person commits a misdemeanor of the first degree if he possesses a weapon in the buildings of, on the grounds of, or in any conveyance providing transportation to or from any elementary or secondary publicly-funded educational institution, any elementary or secondary private school licensed by the Department of Education or any elementary or secondary parochial school.

(c) Defense.--It shall be a defense that the weapon is possessed and used in conjunction with a lawful supervised school activity or course or is possessed for other lawful purpose.