calcium

[kal-see-uh m] /ˈkæl si əm/

noun, Chemistry, Biology

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

1800-10; calc- + -ium

Examples from the web for calcium

Ionized calcium is calcium that is freely flowing in your blood and not attached to proteins.
The mineral in question is calcium carbonate, the defining ingredient of limestone.
Calcite and aragonite are the two crystal forms of calcium carbonate, a property of minerals geologists call dimorphism.
Plant scientists have long suspected calcium as a key player in controlling the action of the stomata.
The key ingredient is limestone, mostly calcium carbonate, the remains of shelled marine creatures.
About half of the copper and calcium are in their immediately available forms.
Hypocalcemia is an abnormally low blood calcium level.
Many species of invertebrate have shells or skeletons made of calcium carbonate.
Strong bones need calcium and one of the best ways to get it is from dairy products.
In reefs, all the builders die: the bricks are calcium carbonate shells.

British Dictionary definitions for calcium

calcium

/ˈkælsɪəm/

noun

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

C19: from New Latin, from Latin calx lime

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.

calcium in Medicine

calcium cal·ci·um (kāl'sē-əm)
n.
Symbol Ca
A soft metallic element that is a basic component of animals and plants and constitutes [approx] 3 percent of Earth's crust. It occurs naturally in limestone, gypsum, and fluorite. Atomic number 20; atomic weight 40.08; melting point 842°C; boiling point 1,484°C; specific gravity 1.55; valence 2.

calcium in Science

calcium

(kāl'sē-əm)
Symbol Ca
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.