A built-in camera mechanism containing a metal or fabric curtain for exposing film. It sits in front of the focal plane (just in front of the film).
A shutter located near the focal plane; usually consisting of a curtain with a slot which is pulled across the focal plane to make the exposure.
A camera mechanism that admits light to expose film by opening a slit just in front of the film (focal) plane.
An opaque curtain containing a slit that moves directly across in front of the film in a camera and allows image-forming light to strike the film.
In camera design, a focal-plane shutter is a type of photographic shutter. It is so called because it is right in front of the focal (film) plane of the camera.