Source : Webster's Revised Unabridged Dictionary (1913)

Redeemer \Re*deem"er\ (r?*d?m"?r), n.
   1. One who redeems.

   2. Specifically, the Savior of the world, Jesus Christ.

Source : WordNet®

Redeemer
     n 1: a teacher and prophet born in Bethlehem and active in
          Nazareth; his life and sermons form the basis for
          Christianity (circa 4 BC - AD 29) [syn: {Jesus}, {Jesus
          of Nazareth}, {the Nazarene}, {Jesus Christ}, {Christ},
          {Savior}, {Saviour}, {Good Shepherd}, {Deliverer}]
     2: someone who redeems or buys back (promissory notes or
        merchandise or commercial paper etc.)