Calx

Definition:

(n.) Quicklime.
(n.) The substance which remains when a metal or mineral has been subjected to calcination or combustion by heat, and which is, or may be, reduced to a fine powder.
(n.) Broken and refuse glass, returned to the post.

Compare calx with other words:

calcigenous vs. calx

calciform vs. calx

calcination vs. calx

calx vs. phlogiston

calcium vs. calx