Source : Free On-Line Dictionary of Computing

dot pitch
     
         The distance between a dot and the closest dot of
        the same colour (red, green or blue) on a color {CRT}.  Dot
        pitch is typically from 0.28 to 0.51 mm but large presentation
        monitors may go up to 1.0 mm.  The smaller the dot pitch, the
        crisper the image, 0.31 or less provides a sharp image,
        especially when displaying text.
     
        Dot pitch measurements between conventional tubes and {Sony}'s
        {Trinitron} tubes are roughly, but not exactly comparable.
        Sony's {CRT}s use vertical stripes, not dots, and its
        measurement is the distance between stripes, not the diagonal
        distance between dots.
     
        ["The Computer Glossary", Alan Freedman].
     
        (1995-12-14)