What does "caesium" mean?

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

What is a synonym for "caesium"?

Common synonyms include: atomic number 55, cesium, cs.

/ˈsiːzi.əm/ noun

noun ·Rare ·Advanced level

Noun

1
The chemical element (symbol Cs) with an atomic number of 55. It is a soft, gold-colored, highly reactive alkali metal. uncountable
2
a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metal wordnet

"Lithium, sodium, potassium, rubidium, caesium and francium are alkali metals."

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