- 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. Symbol: Ca; atomic weight: 40.08; atomic number: 20; specific gravity: 1.55 at 20°C.
Origin of calcium
Examples from the Web for calcium
Fat-free or skim milkEveryone knows milk is an excellent source of calcium that will keep your bones in tip-top shape.10 Ways to Stay Hydrated (That Aren’t Water)
July 25, 2014
The rhino beetle—fried, stewed, grilled, or roasted—is high in calcium and protein.Cicadas, Grasshoppers, Locusts, Ants Among the Tastiest Insects
May 14, 2013
At night we drank a beverage we called “CalMag,” a terrible mixture of calcium, magnesium, vinegar, and water.Scientology’s Sea Org: A Story of Escape for Katie Holmes and Suri Cruise
July 6, 2012
She tells us what happens when the balance is ripped apart by the release of calcium and magnesium into the atmosphere.Chris Hedges and Joe Sacco Chronicle Mining Catastrophes in West Virginia
Chris Hedges, Joe Sacco
June 14, 2012
And many are packed with nutrients like zinc, iron, and calcium.Forget the Starbucks Backlash—We Should Be Eating More Bugs
April 24, 2012
The most satisfactory of these substances is chloride of calcium .Researches on Cellulose
C. F. Cross
With calcium it is said to yield a scarlet, sparingly soluble in water.Field's Chromatography
I do not grant any one the pleasure of re-using his chloride of calcium.The Man With The Broken Ear
More commonly it is found associated with calcium carbonate.
Calcium sulphate, like the carbonate, occurs in many forms in nature.
- 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
Word Origin and History for calcium
coined 1808 by English chemist Sir Humphrey Davy (1778-1829), who first succeeded in isolating it, from Latin calx (genitive calcis) "limestone" (see chalk (n.)) + metallic element ending -ium.
- A soft metallic element that is a basic component of animals and plants and constitutes approximately 3 percent of Earth's crust. It occurs naturally in limestone, gypsum, and fluorite. Atomic number 20.
- 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. See Periodic Table.