The Collaborative International Dictionary of English v.0.48:
magnesium oxide \magnesium oxide\ n. (Chem.) Magnesia. [WordNet 1.5]WordNet (r) 3.0 (2006):
magnesium oxide n 1: a white solid mineral that occurs naturally as periclase; a source of magnesium [syn: periclase, magnesia, magnesium oxide]