1. plural of caesium; a soft, silvery-white metallic chemical element with atomic number 55, highly reactive and used in atomic clocks and photoelectric cells
Usage: Also spelled 'cesiums' in U.S. English; Chemistry term; Countable noun in technical contexts referring to multiple samples or quantities

Examples

• The laboratory stored several caesiums in sealed glass containers.
• Caesiums are among the most reactive metals on the periodic table.
• Atomic clocks rely on the precise vibrations of caesiums atoms.
• Different isotopes of caesiums have varying half-lives.
• The chemist compared the properties of caesiums with other alkali metals.