What does it mean to call someone the master?

1. Teacher's collective name. 2. A surname, a teacher or a combination of Shao Shi and Shao Fu. 3. honorifics for monks and Taoists. 4. Courtesy of officials in yamen. 5. A courtesy title for a craftsman with special skills.

A master is relative to an apprentice. The master is called after the apprentice has learned from him (the apprentice needs to find three teachers, one tutor, one tutor and one tutor, otherwise the master will not accept the apprentice).

Used as a title of respect for an authority or skilled person in a certain industry.