caesium Meaning, Definition & Usage

  1. noun a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metal
    cesium; Cs; atomic number 55.

WordNet


Cæ"si*um noun (Also<
  • Caesium
  • Cæsium
)
Etymology
NL., from L. caesius bluish gray.
Definitions
  1. (Chem.) A rare alkaline metal found in mineral water; -- so called from the two characteristic blue lines in its spectrum. It was the first element discovered by spectrum analysis, and is the most strongly basic and electro-positive substance known. Symbol Cs. Atomic weight 132.6.

Webster 1913