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Vinony

caesium

noun

  1. element with the atomic number of 55
L18237 on Wikidata ↗

Wiktionary

Pronunciation: /ˈsiːzi.əm/

noun

Etymology: From Latin caesius (“sky-blue”), in reference to the radiation spectra, + -ium.

  1. The chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal.