Source : Webster's Revised Unabridged Dictionary (1913)

Baron \Bar"on\, n. [OE. baron, barun, OF. baron, accus. of ber,
   F. baron, prob. fr. OHG. baro (not found) bearer, akin to E.
   bear to support; cf. O. Frisian bere, LL. baro, It. barone,
   Sp. varon. From the meaning bearer (of burdens) seem to have
   come the senses strong man, man (in distinction from woman),
   which is the oldest meaning in French, and lastly, nobleman.
   Cf. L. baro, simpleton. See {Bear} to support.]
   1. 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.

   Note: ``The tenants in chief from the Crown, who held lands
         of the annual value of four hundred pounds, were styled
         Barons; and it is to them, and not to the members of
         the lowest grade of the nobility (to whom the title at
         the present time belongs), that reference is made when
         we read of the Barons of the early days of England's
         history . . . . Barons are addressed as 'My Lord,' and
         are styled 'Right Honorable.' All their sons and
         daughters 'Honorable.''' --Cussans.

   2. (Old Law) A husband; as, baron and feme, husband and wife.
      [R.] --Cowell.

   {Baron of beef}, two sirloins not cut asunder at the
      backbone.

   {Barons of the Cinque Ports}, formerly members of the House
      of Commons, elected by the seven Cinque Ports, two for
      each port.

   {Baron of the exchequer}, the judges of the Court of
      Exchequer, one of the three ancient courts of England, now
      abolished.

Source : WordNet®

Baron
     n 1: a nobleman (in various countries) of varying rank
     2: a British peer of the lowest rank
     3: a very wealthy or powerful businessman; "an oil baron" [syn:
         {big businessman}, {business leader}, {king}, {magnate},
        {mogul}, {power}, {top executive}, {tycoon}]