noun
- Plural of millimicron; units of length equal to one thousandth of a micron, or 10⁻⁹ meters; now called nanometers.
Usage: dated or archaic term; largely replaced by the modern unit 'nanometer' in scientific contexts
Examples
- The wavelength of visible light ranges from about 400 to 700 millimicrons.
- Early spectroscopy measurements were often recorded in millimicrons before the nanometer became standard.
- Ultraviolet radiation has wavelengths shorter than 400 millimicrons.
- The filter was designed to block wavelengths below 300 millimicrons.