Often times, you will hear the term "fiduciary" being used to describe a person who has certain responsibilities in relation to a transaction or other matter.  However, the term is used to define not just the person, but the relationship between two or more parties.  The law recognizes that certain relationships carry with them special obligations to one another.  For example, everyone can recognize that a doctor and patient relationship should be built on confidence, trust, and good faith.  The relationship between a doctor and a patient is a fiduciary one.  If you are the guardian of an adult or child, you also stand in a fiduciary role to that person.  Corporate executives are fiduciaries to their investors and owners.  Business partners are fiduciaries to each other.

The term is derived from the Roman law, and means (as a noun) a person holding the character of a trustee, or a character analogous to that of a trustee,in respect to the trust and confidence involved in it and the scrupulous good faith and candor which it requires. Thus, a person is a fiduciary who is invested with rights and powers to be exercised for the benefit of another person.  As an adjective it means of the nature of a trust; having the characteristics of a trust; analogous to a trust; relating to or founded upon a trust or confidence.