- The crumbly residue left after a mineral or metal has been calcined or roasted.
- In <em>anatomy</em>, the heel: commonly used in the Latin genitive (<em>calcis</em>), as in <internalXref urlencoded="os%20calcis">os calcis</internalXref>, the heel-bone or calcaneum.
- Lime or chalk.
- The ashy substance which remains after metals, minerals, etc., have been calcined. Metallic calxes are now generally called <internalXref urlencoded="oxids">oxids</internalXref>.
- Broken and refuse glass, which is restored to the pots.
- 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.
- Broken and refuse glass, returned to the post.
- The substance which remains after a metal or mineral has been thoroughly burnt, seen as being the essential substance left after the expulsion of <xref>phlogiston</xref>.
- the <xref>oxide</xref> left after <xref>calcination</xref> of a metal.
- <xref>calcium oxide</xref>
- a white crystalline oxide used in the production of calcium hydroxide