WordNet (r) 3.0 (2006):

scanner
    n 1: someone who scans verse to determine the number and
         prosodic value of the syllables
    2: an electronic device that generates a digital representation
       of an image for data input to a computer [syn: scanner,
       digital scanner, image scanner]
    3: a radar dish that rotates or oscillates in order to scan a
       broad area
    4: a radio receiver that moves automatically across some
       selected range of frequencies looking for some signal or
       condition; "they used scanners to monitor police radio
       channels" [syn: scanner, electronic scanner]

The Free On-line Dictionary of Computing (30 December 2018):

scanner

   1. An input device that takes in an optical image and
   digitises it into an electronic image represented as binary
   data.  This can be used to create a computerised version of a
   photo or illustration.

   A scanner may be linked to optical character recognition
   software allowing printed documents to be converted to
   electronic text without having to type them in at a keyboard.

   2. lexical analyser.

   (1995-02-14)