calx vs burnt lime

calx and burnt lime both are nouns.

Word	Noun	Adjective	Verb	Adverb
calx	Yes	No	No	No
burnt lime	Yes	No	No	No

As nouns, calx and burnt lime are synonyms defined as:

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

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

calx (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