From DMJ Productions

Mentorship is the patronage, influence, guidance, or direction given by a mentor. A mentor is someone who teaches or gives help and advice to a less experienced and often younger person. In an organizational setting, a mentor influences the personal and professional growth of a mentee. Most traditional mentorships involve having senior employees mentor more junior employees, but mentors do not necessarily have to be more senior than the people they mentor. What matters is that mentors have experience that others can learn from.

According to the Business Dictionary, a mentor is a senior or more experienced person who is assigned to function as an advisor, counsellor, or guide to a junior or trainee.

From Wikipedia