D defs.my
Entry 1 sense Webster, 1913

Magnesia

/măg-nēzh'-ə/ · Mag·ne·si·a · IPA /ˌmæɡˈniʒə/
01 n. A light earthy white substance, consisting of magnesium oxide (MgO), and obtained by heating magnesium hydrate or carbonate, or by burning …
  1. 1.
    A light earthy white substance, consisting of magnesium oxide (MgO), and obtained by heating magnesium hydrate or carbonate, or by burning magnesium. It has a slightly alkaline reaction, and is used in medicine as a mild antacid laxative. See Magnesium.(Chem.) See: Magnesium
Phrases & compounds
Magnesia alba — a bulky white amorphous substance, consisting of a hydrous basic carbonate of magnesium, and used as a mild cathartic.