Source : WordNet®

nanometre
     n : a metric unit of length equal to one billionth of a meter
         [syn: {nanometer}, {nm}, {millimicron}, {micromillimeter},
          {micromillimetre}]

Source : Free On-Line Dictionary of Computing

nanometre
     
         10^-9 metres; one thousand millionth part of a metre.
     
        The wavelength of visible light and dimensions in
        {nanotechnology} are typically measured in nanometres.
     
        (2003-05-02)