noun (n)

• 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(noun.substance)

  Synonym:
  atomic number 20, ca
  

  source: wordnet30
• 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.(noun)

  source: webster1913