Calx

n.	1.
	1.	(Chem.) Quicklime.
	2.	Broken and refuse glass, returned to the post.

Noun

1.

calx - a white crystalline oxide used in the production of calcium hydroxide Synonyms: burnt lime, calcined lime, calcium oxide, fluxing lime, quicklime, unslaked lime, lime

ash, ashes, brand, carbon, charcoal, cinder, clinker, coal, coke, coom, dross, fume, lava, reek, scoria, slag, smoke, smudge, smut, soot, sullage