Source : Webster's Revised Unabridged Dictionary (1913)

Outfield \Out"field`\, n.
   1. Arable land which has been or is being exhausted. See
      {Infield}, 1. [Scot.]

   2. A field beyond, or separated from, the inclosed land about
      the homestead; an uninclosed or unexplored tract. Also
      used figuratively.

            The great outfield of thought or fact. --Trench.

   3. (Baseball) The part of the field beyond the diamond, or
      infield. It is occupied by the fielders.

   4. (Cricket) The part of the field farthest from the batsman.

Source : WordNet®

outfield
     n : the area of a baseball playing field beyond the lines
         connecting the bases [ant: {baseball diamond}]