magnesium oxide vs magnesia

magnesium oxide and magnesia both are nouns.

Word	Noun	Adjective	Verb	Adverb
magnesium oxide	Yes	No	No	No
magnesia	Yes	No	No	No

As nouns, magnesium oxide and magnesia are synonyms defined as:

magnesium oxide and magnesia: a white solid mineral that occurs naturally as periclase; a source of magnesium

Other synonyms of magnesium oxide include periclase.

magnesium oxide (noun)	magnesia (noun)
a white solid mineral that occurs naturally as periclase; a source of magnesium	a white solid mineral that occurs naturally as periclase; a source of magnesium