The words mentor, advisor, and coach are frequently used interchangeably. However, they are actually quite different. Understanding the distinction will ensure that you get–and provide–the appropropriate level of guidance.
Mentor: someone who has achieved what you want to achieve, and is available to respond to questions from you, in order to help you achieve your goals more quickly and with less friction. A mentor generally waits to be asked for help, and is reactive more than proactive.
Advisor: someone who has expertise in a subject matter of importance to you. This person can make recommendations pertaining to these areas of expertise, often with some research or analysis regarding your question. An advisor provides advice specific to your situation, and relating to a particular area, like tax, or marketing, or child-rearing, but is not necessarily someone who has ever been in the specific role of his or her clients.
Coach: someone who is an expert on the processes required to achieve success. This person works with you on an ongoing basis to achieve your specific objectives, whether or not he or she has actually achieved such goals him or herself. Coaches are generally great at asking questions and provoking the coach-ee to identify his or her own solutions, and stay with the coach-ee as he or she works toward the goal.
In business, all three are readily available, but the value they provide can be dramatically different. It is important to be clear on the kind of engagement that makes the most sense to achieveing the objectives at hand.