'Millimicron' definitions:

Definition of 'millimicron'

From: WordNet
noun
A metric unit of length equal to one billionth of a meter [syn: nanometer, nanometre, nm, millimicron, micromillimeter, micromillimetre]

Definition of 'Millimicron'

From: GCIDE
  • 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.]