regent

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One who rules during the minority, absence, or disability of a monarch.
• noun One acting as a ruler or governor.
• noun A member of a board that governs an institution, such as a state university.

from The Century Dictionary.

• To teach or superintend as a regent.
• To direct or control (a person) as a regent.
• To act as a regent of a university.
• Ruling; governing.
• Exercising vicarious authority: as, a prince regent.
• Taking part in the government of a university.
• noun A ruler; a governor: in a general sense.
• noun One who is invested with vicarious authority; one who governs a kingdom in the minority, absence, or disability of the king.
• noun In the old universities, a master or doctor who takes part in the regular duties of instruction or government.
• noun In the State of New York, a member of the corporate body known as the University of the State of New York.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Ruling; governing; regnant.
• adjective Exercising vicarious authority.
• adjective See under Queen, n.
• noun One who rules or reigns; a governor; a ruler.
• noun Especially, one invested with vicarious authority; one who governs a kingdom in the minority, absence, or disability of the sovereign.
• noun One of a governing board; a trustee or overseer; a superintendent; a curator.
• noun (Eng.Univ.) A resident master of arts of less than five years' standing, or a doctor of less than twwo. They were formerly privileged to lecture in the schools.
• noun (Zoöl.) a beautiful Australian bower bird (Sericulus melinus). The male has the head, neck, and large patches on the wings, bright golden yellow, and the rest of the plumage deep velvety black; -- so called in honor of the Prince of Wales (afterward George IV.), who was Prince Regent in the reign of George III.
• noun the members of a corporate body called the University of New York. They have a certain supervisory power over the incorporated institution for Academic and higher education in the State.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One who rules in place of the monarch because the monarch is too young, absent, or disabled.
• noun A member of governing board.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective acting or functioning as a regent or ruler
• noun someone who rules during the absence or incapacity or minority of the country's monarch
• noun members of a governing board