Prelector

n. [ Cf. F. projeteur. ] 1. One who projects a scheme or design; hence, one who forms fanciful or chimerical schemes. L'Estrange. [ 1913 Webster ]

2. an optical instrument which projects an image from a transparency or an opaque image onto a projection screen or other surface, using an intense light and one or more lenses to focus the image. The term projector by itself is usually used for projection of transparent images by passing the light beam through the image; a projector which projects an image of an opaque object is now ususally referred to as an overhead projector. In projection of this latter form the projection is accomplished by means of a combination of lenses with a prism and a mirror or reflector. Specific instruments have been called by different names, such as balopticon, radiopticon, radiopticon, mirrorscope, etc. [ Webster 1913 Suppl. +PJC ]

Slide projector a projector for displaying images from individual transparencies (slides), each mounted in a separate frame suited to the mechanics of the projector. --
movie projector a projector which displays a series of images from a roll of transparent film in rapid sucession, thus giving the impression of showing a scene with motion as it originally was recorded. --
overhead projector see projector{ 2 }, above. --> [ PJC ]