のぞき穴 ドアスコープ 门镜 猫眼(门)
A small opening through a [[door]] allowing a person to look from the inside to the outside.  Most modern peepholes incorporate a [[fisheye]] lens to allow for a wider field of view while also limiting the ability to peer in from the outside.

Not to be confused with [[peeking]].

For when the viewer appears to be looking through it, use [[pov peephole]] instead, and only add [[peephole]] if one is present in the image itself.

h4. External links

* "Wikipedia: Peephole":[https://en.wikipedia.org/wiki/Peephole]
peephole