[kal-see-uh
m] 
| 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. |
| cal·ci·um (kāl'sē-əm) n. Symbol Ca A silvery, moderately hard metallic element that constitutes approximately 3 percent of the earth's crust and is a basic component of most animals and plants. It occurs naturally in limestone, gypsum, and fluorite, and its compounds are used to make plaster, quicklime, Portland cement, and metallurgic and electronic materials. 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 Table at element. [Latin calx, calc-, lime; see calx + -ium.] |
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 (kāl'sē-əm) Pronunciation Key
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. |