Peephole

A peephole, peekhole, spyhole, doorhole, magic eye, magic mirror or door viewer is a small, round opening through a door from which a viewer on the inside of a dwelling may "peek" to see directly outside the door. The lenses are made and arranged in such a way that viewing is only possible in one direction. The opening is typically no larger than the diameter of a dime (0.7 inches, 18 mm).

For the System of a Down song, see System of a Down (album).
For the computer compiler techniques, see peephole optimization.

In a door, usually for apartments or hotel rooms, a peephole enables to see outside without opening the door nor revealing one's presence. Glass peepholes are often fitted with a fisheye lens to allow a wider field of view from the inside.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.