Source : WordNet®

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: {digital
        scanner}, {image scanner}]
     3: a radar dish that rotates or oscillates in order to scan a
        broad area
     4: a radio receiver that that moves automatically across some
        selected range of frequencies looking for for some signal
        or condition; "they used scanners to monitor police radio
        channels" [syn: {electronic scanner}]

Source : Free On-Line Dictionary of Computing

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)