A unit of size equal to one thousandth (10-3) of a micrometer or one billionth (10-9) of a meter.

a product of length corresponding to one thousandth of a micron

The thousandth section of a micron or the millionth section of a millimeter; -- a unit of size used in measuring light waves, etc.

A unit of length (μμ) corresponding to 10 Ångström devices, .001 microns, or .000001 millimeters: often used in microscopy or in stating wave-lengths of light.

a metric product of length corresponding to one billionth of a meter

A theory or system of social reform which contemplates a complete reconstruction of society with a more just and equitable distribution of property and labor In popular usage the term is often employed to indicate any lawless revolutionary social scheme See Communism Fourierism Saint Simonianism forms of socialism...

## How would you define millimicron?