Source : Free On-Line Dictionary of Computing

Longitudinal Redundancy Check
     
         (LRC, Block Redundancy Check) An
        {error checking} method that generates a {longitudinal parity}
        {byte} from a specified {string} or block of {bytes} on a
        longitudinal track.
     
        The longitudinal parity byte is created by placing individual
        bytes of a string in a two-dimensional {array} and performing
        a {Vertical Redundancy Check} vertically and horizontally on
        the array, creating an extra byte.  This is an improvement
        over the VRC because it will catch an odd number of errors in
        the individual characters of the string.
     
        (2001-04-28)