1. Someone whose business is to cut hair and to shave or trim beards: Jack's father was a barber who had a shop downtown where usually men came to have their hair cut and face shaved.
2. Originally, a regular practitioner of surgery and dentistry: A barber was often called barber-surgeons, however they were restricted to haircutting and dentistry under Henry VIII.

A history page about barbers and barber poles.

To cut or trim a person's hair: Jenny wanted to barber her sister's hair, so she had to get special scissors to do the job.