scanner

noun

1. a person or thing that scans.
2. optical scanner.See under optical scanning.
3. Photography. 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 especially by police, firefighters, and the press, that continuously tunes to preselected frequencies, broadcasting any signal that it detects.
8. Medicine/Medical, Biology. a device for examining a body, organ, tissue, or other biologically active material.

noun

1. a person or thing that scans
2. a device, usually electronic, used to measure or sample the distribution of some quantity or condition in a particular system, region, or area
3. an aerial or similar device designed to transmit or receive signals, esp radar signals, inside a given solid angle of space, thus allowing a particular region to be scanned
4. any of various devices used in medical diagnosis to obtain an image of an internal organ or partSee CAT scanner, nuclear magnetic resonance scanner, ultrasound scanner
5. informal a television outside broadcast vehicle
6. short for optical scanner
7. printing an electronic device which scans printed material and converts it to digital form

n.1550s, “person who examines critically,” agent noun from scan (v.). From 1927 as a type of mechanical device, in mid-20c. use especially of radar and medical devices; later of computer accessories.