- the usual US spelling of caesium
WordReference Random House Unabridged Dictionary of American English © 2025
ce•si•um
(sē′zē əm),USA pronunciation n.
- Chemistrya rare, highly reactive, soft, metallic element of the alkali metal group, used chiefly in photoelectric cells. Symbol: Cs;
at. wt.: 132.905;
at. no.: 55;
sp. gr.: 1.9 at 20°C;
melts at 28.5°C.
- Neo-Latin, special use of Latin caesium, neuter of caesius bluish-grey; see -ium
- 1930–35
Collins Concise English Dictionary © HarperCollins Publishers::
'cesium' also found in these entries (note: many are not synonyms or translations):
Cs
- alkali metal
- atomic clock
- caesium
- cesium 137
- mosaic
- photocathode
- radiocesium
- second