The Collaborative International Dictionary of English v.0.48:
barber pole \barber pole\, barbers pole \barbers pole\n. a pole with red and white spiral stripes; -- usually found outside a barbershop. Note: It is often electrically powered, so as to be turning when the barbershop is open for business and stationary when the shop is closed. It symbolizes the practise of surgery, some aspects of which which used to be performed by barbers. [PJC]