Other mistake: Toward the end, when Mike is snuggling at the window with Sully, the candle on the wall near them isn't lit. But there is ominous light about them, obviously from the studio set.
The Tempest - S5-E10
Other mistake: Smoke from the burning Thanksgiving dinner starts wafting from the stove just moments before a strong wind from a coming storm blasts through the window. Yet somehow Michaela doesn't notice the smell just moments before going outside with Katie.
Other mistake: When Sully's wrist gets scraped while moving the examining bed off the wagon, Dr. Mike merely dabs over it with some disinfectant, instead of thoroughly cleansing the wound with a wet cloth before suturing like a normal doctor.
Answer: A Cooper was someone who made various things out of wood including wooden caskets and even barrels.