- A lighting unit which concentrates light within a limited solid angle by means of lenses or mirrors.
- A line dropped perpendicularly from a point to a plane surface.
- A device which transmits a beam of light, especially that conveying images, onto a surface, such as a translucent screen. An overhead projector is an example.
- A device or object, such as a horn, which serves to direct and intensify sound.
- noun a piece of equipment for projecting the image from film onto a screen and for playing back recorded sound from tracks on the film
- A projection unit that uses glass slides to create atmosphericlighting on stage. Less frequently, projectors are used to projectstill or moving images behind actors, as in the Polykran and LaternaMagica of Josef Svoboda and in such plays as Joan Littlewood'smusical documentary Oh, What a Lovely War! (1963). When certainweather and natural effects are required (such as stormy skies, snow,rain, and fire, etc.) special-effects projectors are employed. InAmerica, this latter device is known as a sciopticon, whichis the old Victorian name for a magic lantern used to project photographs(one was exhibited in London's South Kensington Museum in 1876).
- noun an apparatus for making pictures appear on a screen