Search microgram (μg, mcg) microgram (μg, mcg) /mī″krəgram/ , a unit of measurement of mass equal to one millionth (10−6) of a gram. See also gram. Tweet Telegram VK Random Words low-cholesterol diet calcium sulfate (CaSO4) toxic epidermal necrolysis (TEN) polyarteritis nodosa passiflora Elaprase Nauheim bath hyperglycogenolysis vitamin K1