Source : WordNet®

megabyte
     n : a unit of information equal to one million (1,048,576) bytes
         [syn: {MB}]

Source : Free On-Line Dictionary of Computing

megabyte
     
         ({MB}, colloquially "meg") 2^20 = 1,048,576 {bytes} =
        1024 {kilobytes}.  1024 megabytes are one {gigabyte}.
     
        The text of a six hundred page paperback book would require
        about a megabyte of {ASCII} storage.
     
        See {prefix}.
     
        (1997-03-26)