A very common metric unit of mass equal to 0.001 gram or 1000 micrograms (g or mcg). One milligram equals approximately 0.015432 grain or 35.274 x 10-6 ounce
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}