Source : WordNet®

MB
     n 1: a unit of information equal to one million (1,048,576) bytes
          [syn: {megabyte}]
     2: (a British degree) a bachelor's degree in medicine [syn: {Bachelor
        of Medicine}]

Source : Free On-Line Dictionary of Computing

MB
     
         (Or "Mb") {megabytes} or {megabits}.  When referring to
        the size or data transfer rate of a storage device which is
        accessed in multiples of eight bits (e.g. {RAM}, {hard disk})
        this almost certainly means megabytes, but when referring to
        the data transfer rate of a communications system it probably
        means {megabits}.  Some years ago, it is claimed, "MB" always
        meant megabytes and "Mb" meant megabits but recently this
        useful distinction has been lost.
     
        (1996-09-22)