say it: SEE-zee-uhm
cesium is a noun meaning "a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metal". It carries one recorded sense.
a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metal
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for cesium come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.