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cesium Definition

ce·sium (sē′zē əm)

noun

a soft, silver-white, ductile, metallic chemical element, one of the alkali metals and the most electropositive of all the elements: it ignites in air, reacts vigorously with water, and is used in photoelectric cells: symbol, Cs; at. no., 55: a radioactive isotope (cesium-137) with a half-life of 30.17 years is a fission product and is used in cancer research, radiation therapy, etc.

Etymology: ModL, orig. neut. of L caesius, bluish-gray (< IE base *(s)kai-, bright > -hood): so named (1860) by Robert Wilhelm Bunsen because of the blue line seen in the spectroscope

cesium Usage Examples

Modifies a noun

  • atom: In around 1960 the cesium atom was in use in atomic clocks.
  • iodide: Optical absorption spectra of cesium iodide ( CsI ) at pressures up to 60 GPa.

Noun used with modifier

  • name: It burns with a brilliant blue flame - the name cesium derives from the sky-blue lines in its spectrum.

Browse dictionary entries near cesium

  1. ‹ cesarean (section)
  2. ‹ cesarean
  3. ‹ cervix
  4. ‹ cervine
  5. ‹ Cervin
  6. ‹ cervid
  7. ‹ cervico-
  8. ‹ cervicitis
  9. ‹ cervices
  10. ‹ cervical cap
  1. České Budějovice ›
  2. Československo ›
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