A projectionist is a person who operates a movie projector, particularly as an employee of a movie theater. Projectionists are also known as "operators".
Projectionist
Two projectors installed in a changeover configuration. The machine in the background will show the first reel, at the end of which the projectionist will 'change over' to reel 2, which is threaded on the projector in the foreground. If the procedure is performed correctly, the audience will be unaware that it has happened.
The projector inside the booth used by the projectionist
The view from a projectionist's booth at the Ultimate Palace Cinema in Oxford
A movie projector is an opto-mechanical device for displaying motion picture film by projecting it onto a screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras. Modern movie projectors are specially built video projectors.
35 mm movie projector in operation
An early projector and seats from a movie theater
1910's 35mm hand-cranked tinplate toy movie projector manufactured by Leonhard Müller in Nuremberg, Germany.
35 mm Kinoton FP30ST movie projector, with parts labeled. (Click thumbnail for larger text.)