cesium

noun ce·si·um \ ˈsē-zē-əm also -zhē- \

Updated on: 14 Apr 2018

Definition of cesium

: a silver-white soft ductile element of the alkali metal group that is the most electropositive element known and that is used especially in photoelectric cells — see Chemical Elements Table

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Recent Examples of cesium from the Web

The calibration is done with the alkali metal cesium.

— jay bennett, Popular Mechanics, "The Centuries-Long Quest to Measure One Second," 24 Mar. 2017
The concentrations of radioactive cesium near Japan, for example, were much higher than the concentrations along the west coast of the US.

— rachel becker, The Verge, "Katsuko Saruhashi turned radioactive fallout into a scientific legacy," 22 Mar. 2018
A few months after that incident, in Tokyo, a protester was arrested for landing a drone carrying a harmless amount of radioactive cesium on the prime minister’s office.

— michael laris, Washington Post, "Drones keep entering no-fly zones over Washington, raising security concerns," 13 Jan. 2018
After preliminary measurements are completed, the physicists plan to install a low-temperature cesium iodide detector to search for dark matter.

— pallava bagla, Science | AAAS, "India joins hunt for dark matter," 31 Aug. 2017
The Chinese clock, however, is less advanced than its European counterpart, which will use cold cesium atoms.

— edwin cartlidge, Science | AAAS, "China’s atomic clock passes space test," 20 Sep. 2017
The city of Soma last year set up municipal incinerators specially designed to burn carcasses and filter out radioactive cesium.

— kimiko de freytas-tamura, Orange County Register, "Six years after the Fukushima disaster, a new danger looms: radioactive boars," 10 Mar. 2017
Leap seconds are used to fill in the gap and make Earth’s observed speed align with our most accurate clocks—atomic devices that define a second by measuring the regular decay of radioactive elements such as cesium.

— yomiuri shimbun, National Geographic, "2016 Will Be One Second Longer Than Expected," 8 July 2016
Stuhlinger wrote that cesium would make a more efficient propellant than rubidium.

— david s. f. portree, WIRED, "Ernst’s Ions Week on Beyond Apollo: The Cosmic Butterfly (1954)," 9 Apr. 2012

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Origin and Etymology of cesium

New Latin, from Latin caesius bluish gray

NEW! Time Traveler

First Known Use: 1861

in the meaning defined above

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Medical Dictionary

cesium

noun ce·si·um

variants: or chiefly British caesium play \ˈsē-zē-əm\

medical Definition of cesium

: a silver-white soft ductile element of the alkali metal group that is the most electropositive element known and that is used especially in photoelectric cells —symbol Cs — see Chemical Elements Table