calcium oxide vs burnt lime

calcium oxide and burnt lime both are nouns.

Word	Noun	Adjective	Verb	Adverb
calcium oxide	Yes	No	No	No
burnt lime	Yes	No	No	No

As nouns, calcium oxide and burnt lime are synonyms defined as:

calcium oxide and burnt lime: a white crystalline oxide used in the production of calcium hydroxide

Other synonyms of calcium oxide include calcined lime, calx, fluxing lime, lime, quicklime, unslaked lime.

calcium oxide (noun)	burnt lime (noun)
a white crystalline oxide used in the production of calcium hydroxide	a white crystalline oxide used in the production of calcium hydroxide