Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Projector \Pro*ject"or\, n. [Cf. F. projeteur.]
One who projects a scheme or design; hence, one who forms fanciful or chimerical schemes.
--L'Estrange.-
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.
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.
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Wiktionary
n. A projector that projects an image over the heads of the viewers onto a screen in front of them
WordNet
n. a projector operated by a speaker; projects the image over the speaker's head
Wikipedia
An overhead projector is a variant of slide projector that is used to display images to an audience.
Usage examples of "overhead projector".
The doctor insisted on a proper lectern, and one as big as a pulpit was found in the former office of Niccolo Machiavelli adjacent to the salon and brought on a tall hand truck, along with the palazzo's overhead projector.
The overhead projector produced a scene of desert to a horizon of rolling dunes.
Avi has detached the screen from his big laptop and laid it flat on the surface of the overhead projector, which shines light through the liquid-crystal display and projects a color image on the whiteboard.
He'd need about twenty minutes to get the exhibits printed up on acetate sheets for an overhead projector, something the FBI ought to be prepared for, they both hoped.
Standing at an overhead projector in a darkened penitentiary library, Langdon had shared the Mona Lisa's secret with the prisoners attending class, men whom he found surprisingly engaged-rough, but sharp.
Parker said and put the note on an old-fashioned overhead projector.
Toland flipped on an overhead projector and set a view graph in place.