millimicron

from WordNet (r) 3.0 (2006)

millimicron
    n 1: a metric unit of length equal to one billionth of a meter
         [syn: {nanometer}, {nanometre}, {nm}, {millimicron},
         {micromillimeter}, {micromillimetre}]

from The Collaborative International Dictionary of English v.0.48

Millimicron \Mil"li*mi`cron\, n. [Milli- + micron.]
   The thousandth part of a micron or the millionth part of a
   millimeter; one nanometer; -- a unit of length sometimes used
   in measuring light waves, etc.
   [Webster 1913 Suppl.]