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.
the usual US spelling of caesium
also caesium, rare alkaline metal, 1861, coined by Bunsen and Kirchhoff in 1860 in Modern Latin (caesium), from Latin caesius “blue-gray” (especially of eyes), in reference to the two prominent blue lines in its spectrum, by which it was first identified.
cesium ce·si·um or cae·si·um (sē’zē-əm)
A soft ductile metal, liquid at room temperature, the most electropositive and alkaline of the elements, used in photoelectric cells. Atomic number 55; atomic weight 132.905; melting point 28.4°C; boiling point 671°C; specific gravity 1.87; valence 1.
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.
the radioactive cesium isotope with mass number 137 and a half-life of 33 years: used for gamma irradiation of certain foods and for radiation therapy.
a city in the S Czech Republic, on the Vltava River. noun a city in the S Czech Republic, on the Vltava (Moldau) River. Pop: 94 747 (2007 est) German name Budweis
- Cesky terrier
noun a sturdy long-bodied short-legged variety of terrier with a wavy grey or light brown coat
forming mats; growing in dense tufts. adjective a variant spelling (esp US) of caespitose