1) n. from the Latin fiducia, meaning "trust," a person (or a business like a bank or stock brokerage) who has the power and obligation to act for another (often called the beneficiary) under circumstances which require total trust, good faith and honesty. The most common is a trustee of a trust, but fiduciaries can include business advisers, attorneys, guardians, administrators of estates, real estate agents, bankers, stockbrokers, title companies or anyone who undertakes to assist someone who places complete confidence and trust in that person or company. Characteristically, the fiduciary has greater knowledge and expertise about the matters being handled. A fiduciary is held to a standard of conduct and trust above that of a stranger or of a casual business person. He/she/it must avoid "self-dealing" or "conflicts of interests" in which the potential benefit to the fiduciary is in conflict with what is best for the person who trusts him/her/it. For example, a stockbroker must consider the best investment for the client and not buy or sell on the basis of what brings him/her the highest commission. While a fiduciary and the beneficiary may join together in a business venture or a purchase of property, the best interest of the beneficiary must be primary, and absolute candor is required of the fiduciary. 2) adj. defining a situation or relationship in which a person is acting as a fiduciary for another.