/skan"euhr/ , n.
1. a person or thing that scans.
2. optical scanner. See under optical scanning .
3. Photog. any device for exposing an image on film, a sensitized plate, etc., by tracing light along a series of many closely spaced parallel lines.
4. (in aerial photography) a device for estimating the ratio of aircraft speed to aircraft altitude.
5. a photoelectric device for scanning a picture to determine automatically the density of the hue or value in each area for transmission by wire or radio or for preparation of color process printing plates.
6. a computer-aided electronic system using photoelectric cells to separate copy, as color illustrations, into its primary colors, correct color copy, and produce a set of color separations ready for proofing or printing.
7. Radio. a radio receiver, used esp. by police, firefighters, and the press, that continuously tunes to preselected frequencies, broadcasting any signal that it detects.
8. Med. , Biol. a device for examining a body, organ, tissue, or other biologically active material. Cf. CAT scanner, MRI scanner, PET scanner, sonogram .
[ 1550-60; SCAN + -ER 1 ]