baron

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

• noun A British nobleman of the lowest rank.
• noun A nobleman of continental Europe, ranked differently in various countries.
• noun A Japanese nobleman of the lowest rank.
• noun Used as the title for such a nobleman.
• noun A feudal tenant holding his rights and title directly from a king or another feudal superior.
• noun A lord or nobleman; a peer.
• noun One having great wealth, power, and influence in a specified sphere of activity.
• noun A cut of beef consisting of a double sirloin.

from The Century Dictionary.

• noun In Great Britain, the title of a nobleman holding the lowest rank in the peerage; a member of the baronage: as, Baron Arundell of Wardour; a Scotch baron.
• noun A title of the judges or officers of the English Court of Exchequer, hence called barons of the Exchequer, the president of the court being called chief baron.
• noun In law and heraldry, a husband: as, baron and feme, husband and wife.
• noun On the continent of Europe, especially in France and Germany, a member of the lowest order of hereditary nobility: in Germany, same as Freiherr.

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

• noun A title or degree of nobility; originally, the possessor of a fief, who had feudal tenants under him; in modern times, in France and Germany, a nobleman next in rank below a count; in England, a nobleman of the lowest grade in the House of Lords, being next below a viscount.
• noun (Old Law), rare A husband.
• noun two sirloins not cut asunder at the backbone.
• noun formerly members of the House of Commons, elected by the seven Cinque Ports, two for each port.
• noun the judges of the Court of Exchequer, one of the three ancient courts of England, now abolished.

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

• noun The male ruler of a barony.
• noun A male member of the lowest rank of British nobility.
• noun A particular cut of beef, made up of a double sirloin.

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

• noun a nobleman (in various countries) of varying rank
• noun a very wealthy or powerful businessman
• noun a British peer of the lowest rank