calcium

American  

[kal-see-uhm] / ˈkæl si əm /

noun

Chemistry, Biology.

1. a silver-white divalent metal, occurring combined in limestone, chalk, gypsum, etc., occurring also in vertebrates and other animals, as a component of bone, skeletal mass, shell, etc., and as a necessary element in nerve conduction, heartbeat, muscle contraction, and many other physiological functions. Ca; 40.08; 20; 1.55 at 20°C.

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calcium British  

/ ˈkælsɪəm /

noun

1. a malleable silvery-white metallic element of the alkaline earth group; the fifth most abundant element in the earth's crust (3.6 per cent), occurring esp as forms of calcium carbonate. It is an essential constituent of bones and teeth and is used as a deoxidizer in steel. Symbol: Ca; atomic no: 20; atomic wt: 40.078; valency: 2; relative density: 1.55; melting pt: 842±2°C; boiling pt: 1494°C

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calcium Scientific  

/ kăl′sē-əm /

1. A silvery-white, moderately hard metallic element of the alkaline-earth group that occurs in limestone and gypsum. It is a basic component of leaves, bones, teeth, and shells, and is essential for the normal growth and development of most animals and plants. Calcium is used to make plaster, cement, and alloys. Atomic number 20; atomic weight 40.08; melting point 842 to 848°C; boiling point 1,487°C; specific gravity 1.55; valence 2.

2. See Periodic Table

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Etymology

Origin of calcium

First recorded in 1800–10; calc- + -ium

Example Sentences

Menthol and 1,8-cineole influenced inflammation through TRP channels and calcium signaling.

From Science Daily • Apr. 9, 2026

The U.K. drugmaker asked the Food and Drug Administration to pull its application for the drug leucovorin calcium because it doesn’t market the medicine, according to a regulatory filing posted Thursday.

From The Wall Street Journal • Apr. 9, 2026

In testing, the artificial saliva spray reduced bacterial activity and slowed tooth demineralization -- the process by which teeth lose calcium and phosphate, making them more vulnerable to cavities.

From Science Daily • Apr. 5, 2026

Increasingly, people are opting, too, for a simple, relatively affordable test: a coronary artery calcium scan, or CAC.

From The Wall Street Journal • Mar. 30, 2026

I must admit they’re doing their best to keep me in condition: they’re plying me with dextrose, cod-liver oil, brewer’s yeast and calcium.

From "The Diary of a Young Girl" by Anne Frank