calcium Meaning, Definition & Usage

  1. noun 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
    Ca; atomic number 20.

WordNet

Cal"ci*um noun
Etymology
NL., from L. calx, calcis, lime; cf F. calcium. See Calx.
Definitions
  1. (Chem.) An elementary substance; a metal which combined with oxygen forms lime. It is of a pale yellow color, tenacious, and malleable. It is a member of the alkaline earth group of elements. Atomic weight 40. Symbol Ca. ✍ Calcium is widely and abundantly disseminated, as in its compounds calcium carbonate or limestone, calcium sulphate or gypsum, calcium fluoride or fluor spar, calcium phosphate or apatite.

Webster 1913