calcium
/ˈkælsɪəm/noun
mass noun
- the chemical element of atomic number 20, a soft grey metal. (Symbol: Ca)（化学元素）钙（符号：Ca）。
Calcium is one of the alkaline earth metals. Its compounds occur naturally in limestone, fluorite, gypsum, and other minerals. Many physiological processes involve calcium ions, and calcium salts are an essential constituent of bone, teeth, and shells.
词源