1) French word used in English 2) Metric weight unit 3) One thousandth gram 4) Tiny weight 5) Very small weight 6) Weight unit 1) Mg 
• (n.) Alt. of Milligramme
A measure of weight. A milligram is approximately 450,000 times smaller than a pound and 28,000 times smaller than an ounce.
<unit> One thousandth of a gram. ... Abbreviation: mg ... (12 Jan 1998) ... 
(mg) (mil´ĭ-gram) one thousandth (10−3) of a gram.
(mg) Type: Term Pronunciation: mil′i-gram Definitions: 1. One thousandth of a gram.
Milligram: A unit of measurement of mass in the metric system equal to a thousandth of a gram. A gram is equal to the mass of one milliliter, one thousandth of a liter, of water at 4 degrees C. The abbreviation for milligram is mg.
[n] - 1/1000 gram
milligram One-thousandth of a gram.
mg noun one thousandth (1/1,000) gram
(mg) A milligram is one one-thousandth (1/1,000) of a gram, or about one half million times smaller than a pound. A regular aspirin tablet weighs about 400 milligrams.