Source : Free On-Line Dictionary of Computing

branch prediction
     
         A technique used in some processors
        with {instruction prefetch} to guess whether a {conditional
        branch} will be taken or not and prefetch code from the
        appropriate location.
     
        When a branch instruction is executed, its address and that of
        the next instruction executed (the chosen destination of the
        branch) are stored in the {Branch Target Buffer}.  This
        information is used to predict which way the instruction will
        branch the next time it is executed so that instruction
        prefetch can continue.  When the prediction is correct (and it
        is over 90% of the time), executing a branch does not cause a
        {pipeline break}.
     
        Some later {CPU}s simply prefetch both paths instead of trying
        to predict which way the branch will go.
     
        An extension of the idea of branch prediction is {speculative
        execution}.
     
        (1998-03-14)