The Collaborative International Dictionary of English v.0.48:

Sheepfold \Sheep"fold`\, n.
   A fold or pen for sheep; a place where sheep are collected or
   confined.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sheepfold
    n 1: a pen for sheep [syn: fold, sheepfold, sheep pen,
         sheepcote]