Milligram \Mil"li*gram\, Milligramme \Mil"li*gramme\, n. [F. milligramme; milli- milli- + gramme. See 3d {Gram}.] A measure of mass and weight, in the metric system, being the thousandth part of a gram, very nearly equal to the weight of a cubic millimeter of water, or .01543 of a grain avoirdupois. [1913 Webster] Milliliter