Mentor (noun)

1. An experienced and trusted advisor.
2. A teacher or coach.
3. An experienced person in a company or organization who trains and counsels new employees.
4. A respected senior member of a profession or field who advises and guides a less experienced colleague.

Origin:

Early 17th century: via latin from greek mentōr, the name of the wise old friend of odysseus in homer's odyssey.

Examples:

1. He is a mentor to young entrepreneurs.
2. She is a mentor to new teachers.
3. He is a mentor to young scientists.
4. She is a mentor to young writers.
5. He is a mentor to young athletes.