“Minerals” — nutritionally significant elements composed of only one kind of atom. Minerals are inorganic, i.e., they do not contain carbon as do vitamins and other organic compounds.

“Microorganism” — a microscopic organism, especially a bacterium, fungus, or a protist.

“Micronutrients” — nutrients that the body needs in small amounts. Vitamins and minerals are micronutrients.

“Micrometer” (µm) — one micrometer is equal to one thousandth (1/1,000) of a millimeter or one millionth (1/1,000,000) of a meter.

“Microgram” (µg) — one microgram is equal to one thousandth (1/1,000) of a milligram or one millionth (1/1,000,000) of a gram.