Source : Webster's Revised Unabridged Dictionary (1913)

Connoisseur \Con`nois*seur"\ (?; 277), n. [F. connaisseur,
   formerly connoisseur, fr. conna[^i]tre to know, fr. L.
   cognoscere to become acquainted with; co- + noscere,
   gnoscere, to learn to know. See {Know}, {amd cf}.
   {Cognizor}.]
   One well versed in any subject; a skillful or knowing person;
   a critical judge of any art, particulary of one of the fine
   arts.

         The connoisseur is ``one who knows,'' as opposed to the
         dilettant, who only ``thinks he knows.'' --Fairholt.

Source : WordNet®

connoisseur
     n : an expert able to appreciate a field; especially in the fine
         arts [syn: {cognoscenti}]