What is the 'Normal Distribution'. The normal distribution, also known as the Gaussian or standard normal distribution, is the probability distribution that plots all of its values in a symmetrical fashion, and most of the results are situated around the probability's mean. Values are equally likely to plot either above or below the mean.
Definition of a Mg. A milligram (mg) is a metric system unit that represents a thousandth of a gram. Because of its larger size, a mg is a more commonly used measurement than a mcg. One thousandth of a mg is one mcg, and 1,000 mcg equal one mg.
mg. 1  metric weight unit, weight unit - a decimal unit of weight based on the gram. 2  mcg, microgram - one millionth (1/1,000,000) gram. 3  metric grain, grain - a weight unit used for pearls or diamonds: 50 mg or 1/4 carat.