Progressive Fighting Systems
Hmm, I suppose it's how you define the terms. An instructor sounds like someone who teaches, say, a skill but who's job ends there. If you didn't get it, too bad. A coach suggests someone who is encouraging, wants you to succeed (either at the individual or team level) but can only go so far if they don't know you and your particular quirks, tendencies, good & bad habits and how to correct them. A mentor usually is someone who's gotten to know you, knows all the above, maybe your weaknesses & strengths too and is helping you develop fully to where not only do you reach a specific goal but you've now developed into a person who could now reach the goal(s) on your own and will now become a mentor to a new protégé. Mentor is usually the wisest of the 3. Probably has been all 3. Probably has gotten to where he/she is by a lot of trial & error, mistakes and still didn't quit until getting there.
[@Guy Sparks] you're right on target. At least, that is how I see it . Check out this 2 min clip of Steve Harvey talking about this subject:
Watch "One Easy Way To Find A Mentor" on YouTube