'Peephole' definitions:

Definition of 'peephole'

From: WordNet
noun
A hole (in a door or an oven etc) through which you can peep [syn: peephole, spyhole, eyehole]

Definition of 'Peephole'

From: GCIDE
  • Peephole \Peep"hole`\, n. A hole, or crevice, through which one may peep without being discovered. [1913 Webster]