A white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals WordNet 3.0 & Open English WordNet

Calcium is a chemical element; it has symbol Ca and atomic number 20. Wikipedia

Chemical element with symbol Ca and atomic number 20. Wikipedia Disambiguation

Chemical element with symbol Ca and atomic number 20 Wikidata

A malleable silvery-white metallic element of the alkaline earth group with symbol Ca and atomic number 20; the fifth most abundant element in the earth crust, occurring especially as forms of calcium carbonate. It is an essential constituent of bones and teeth and is used as a deoxidizer in steel. OmegaWiki

The chemical element (Symbol Ca), with an atomic number 20. It is a soft, silvery-white alkaline earth metal which occurs naturally as carbonate in limestone and as silicate in many rocks. Wiktionary

Chemical element of atomic number 20. Wiktionary (translation)