A referral to the dean's office. Coined due to the three sheets of carbon paper they are written on. One goes to the dean for his or her records, another to the teacher who wrote you up, and the last to your parent or guardian.
Mitchell: My dog Tre cursed out his teacher and she ended up writing him up and giving him the ol' three sheeter.
Strategically laying down 2 sheets of toilet paper (in the toilet) before you off-load a big dump. This can be use to appease your significant other, or show respect while using a host's restroom.