Source : Webster's Revised Unabridged Dictionary (1913)

Cupbearer \Cup"bear`er\ (-b[^a]r`[~e]r), n.
   1. One whose office it is to fill and hand the cups at an
      entertainment.

   2. (Antiq.) One of the attendants of a prince or noble,
      permanently charged with the performance of this office
      for his master. ``I was the king's cupbearer.'' --Neh. i.
      11.

Source : WordNet®

cupbearer
     n : the attendant (usually an officer of a nobleman's household)
         whose duty is to fill and serve cups of wine