cesium

or cae·si·um

[ see-zee-uh m ]
/ ˈsi zi əm /

noun

a rare, highly reactive, soft, metallic element of the alkali metal group, used chiefly in photoelectric cells. Symbol: Cs; atomic weight: 132.905; atomic number: 55; specific gravity: 1.9 at 20°C; melts at 28.5°C.

Origin of cesium

1930–35; < New Latin, special use of Latin caesium, neuter of caesius bluish-grey; see -ium

Words nearby cesium

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Example sentences from the Web for cesium

British Dictionary definitions for cesium

cesium
/ (ˈsiːzɪəm) /

noun

the usual US spelling of caesium

Medical definitions for cesium

cesium

n. Symbol Cs

A soft ductile metal, liquid at room temperature, the most electropositive and alkaline of the elements, used in photoelectric cells. Atomic number 55.

Scientific definitions for cesium

cesium
[ sē′zē-əm ]

Cs

A soft, ductile, silvery-white element of the alkali group. It is liquid at room temperature and is the most reactive of all metals. Cesium is used to make photoelectric cells, electron tubes, and atomic clocks. Atomic number 55; atomic weight 132.905; melting point 28.5°C; boiling point 690°C; specific gravity 1.87; valence 1. See Periodic Table.