n.1. a. A British nobleman of the lowest rank.
b. A nobleman of continental Europe, ranked differently in various countries.
c. A Japanese nobleman of the lowest rank.
d. Used as the title for such a nobleman.
2. a. A feudal tenant holding his rights and title directly from a king or another feudal superior.
b. A lord or nobleman; a peer.
3. One having great wealth, power, and influence in a specified sphere of activity: an oil baron.
4. A cut of beef consisting of a double sirloin.