A unit of temperature equal to 0.001 kelvin or 0.001 degree Celsius (ºC). This unit is used mostly by scientists investigating substances cooled very close to absolute zero
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}