Source : Free On-Line Dictionary of Computing

Industry Standard Architecture
     
         (ISA) A {bus} {standard} for {IBM
        compatibles} that extends the {XT bus architecture} to 16
        bits.  It also allows for {bus mastering} although only the
        first 16 {MB} of {main memory} is available for direct access.
        In reference to the XT bus architecture it is sometimes
        referred to as "AT bus architecture".
     
        Compare {EISA}, {MCA}.
     
        (1996-06-25)