From Longman Dictionary of Contemporary Englishcaesiumcae‧si‧um British English, cesium American English /ˈsiːziəm/ noun [uncountable] a soft silver-white metal that is used in photoelectric cells. It is a chemical element: symbol Cs
Examples from the Corpus
caesium• It had a caesium 137 concentration of only 4 becquerels per kilogram.• The best caesium clocks achieve a fractional accuracy and stability of between 10 -13; and 10 -14;.• The study stresses that the levels of caesium observed do not pose any risk to health.• The caesium chloride lattice is thus said to have 8:8 coordination.• The caesium chloride structure, for example, consists of a cubic structure of cations and a cubic structure of anions.Origin caesium (1800-1900) Latin caesius “bluish grey” 