Definition of calcium in English:

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Pronunciation: /ˈkalsēəm/


The chemical element of atomic number 20, a soft gray metal. (Symbol: Ca)

Calcium is one of the alkaline earth metals. Its compounds occur naturally in limestone, fluorite, gypsum, and other minerals. Many physiological processes involve calcium ions, and calcium salts are an essential constituent of bone, teeth, and shells.

Example sentences
  • These active regions often require the presence of a metal ion such as calcium, zinc or iron.
  • Strontium is an element similar to calcium, and follows calcium into teeth and bones.
  • If you tend to be susceptible to cramps, try eating more foods that are high in potassium and calcium.


Early 19th century: from Latin calx, calc- 'lime' (see calx) + -ium.

  • chalk from Old English:

    Old English cealc, the forerunner of chalk, also meant ‘lime’. It came from Latin calx ‘lime’, which is also the source of calcium [19th]. When we say by a long chalk, meaning ‘to a great degree, by far’ (and not by a long chalk, ‘not at all’), the ‘ long chalk’ refers to the length of a line of chalk marks or tallies drawn on a blackboard. This may originally have been in the context of a pub game, where points scored were marked up on the blackboard, or perhaps in the classroom, with a teacher chalking up pupils' marks for schoolwork. In either case, a long line of chalk marks against your name would mean you were a long way ahead of the others.

For editors and proofreaders

Syllabification: cal·ci·um

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