1. 1. A British nobleman of the lowest rank.
   2. A nobleman of continental Europe, ranked differently in various countries.
   3. A Japanese nobleman of the lowest rank.
   4. (Abbr. Bn.) Used as the title for such a nobleman.
2. 1. A feudal tenant holding his rights and title directly from a king or another feudal superior.
   2. 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.

[Middle English, from Old French, probably of Germanic origin.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.