A Professor or a Mentor?

What is the difference between a professor and a mentor? What falls between?

To me, a professor is someone who tells you what they know. This is oftentimes accompanied by the authority of an institution.

• A mentor walks alongside you on your journey. They do not suggest they have all of the answers or tell you what to do.

• A guide is someone who points the way, who oftentimes has traveled a similar path.<