calcium

UK: /ˈkælsɪəm/ US: /ˈkælsiəm/ ,(kal′sē əm)

WordReference Random House Learner's Dictionary of American English © 2025

cal•ci•um /ˈkælsiəm/   n. [uncountable]

1. Chemistry, Nutrition a silver-white metallic element found in limestone and chalk and that also occurs in animals in bone and shell.

WordReference Random House Unabridged Dictionary of American English © 2025

cal•ci•um  (kal′sē əm), n. [Chem., Biol.]

1. Chemistry, Nutrition 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;
   at. wt.: 40.08;
   at. no.: 20;
   sp. gr.: 1.55 at 20°C.

• calc- + -ium 1800–10

Collins Concise English Dictionary © HarperCollins Publishers::

calcium / 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

Etymology: 19th Century: from New Latin, from Latin calx lime