cesium

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

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

Examples of cesium in a Sentence

Recent Examples on the Web

The second is affixed to the motion of the atoms of the element cesium. Brian Resnick, Vox, "The world is about to redefine the kilogram," 15 Nov. 2018 Radiation detectors and dime-sized disks of plutonium and cesium used to make sure the detectors were working properly. Rachel Becker, The Verge, "The US government has trouble keeping track of radioactive material," 17 July 2018 Missing were radiation detectors and small samples of plutonium and cesium used to calibrate them. Dan Goodin, Ars Technica, "Dangerous plutonium stolen from rental car in a hotel parking lot," 16 July 2018 The experts from the Energy Department’s Idaho National Laboratory were sent to San Antonio to retrieve the plutonium and cesium on March 21, 2017, according to a Monday report from The Center for Public Integrity. Ryan Gaydos, Fox News, "Nuclear materials were reportedly stolen in Texas last year -- and they still haven't been found," 16 July 2018 Gases unleashed by the damage exploded, sending plumes of radioactive particles like iodine, cesium, and plutonium into the atmosphere. Vince Beiser, WIRED, "The Robot Assault On Fukushima," 26 Apr. 2018 The particles grab on to ions of cesium, strontium, and other dangerous isotopes in the water, making room for them by spitting out sodium. Vince Beiser, WIRED, "Fukushima’s Other Big Problem: A Million Tons of Radioactive Water," 27 Apr. 2018 The Harvard chemist takes two individual atoms, a sodium and a cesium, each about 10,000 times smaller than a bacterium. Sophia Chen, WIRED, "Chemists Orchestrate the Molecular Union of Two Single Atoms," 27 Apr. 2018 Lasers are used to slow and cool the atoms to near absolute zero, and then more lasers are used to elevate the ball of cesium up the chamber. Jay Bennett, Popular Mechanics, "The Centuries-Long Quest to Measure One Second," 24 Mar. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cesium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of cesium

1861, in the meaning defined above

History and Etymology for cesium

New Latin, from Latin caesius bluish gray

Keep scrolling for more

Learn More about cesium

Statistics for cesium

Last Updated

23 Nov 2018

Look-up Popularity

Time Traveler for cesium

The first known use of cesium was in 1861

See more words from the same year

Keep scrolling for more

More Definitions for cesium

cesium

noun
ce·​si·​um
variants: or chiefly British caesium \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

Keep scrolling for more

More from Merriam-Webster on cesium

Spanish Central: Translation of cesium

Nglish: Translation of cesium for Spanish Speakers

Britannica.com: Encyclopedia article about cesium

Comments on cesium

What made you want to look up cesium? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

living or existing for a long time

Get Word of the Day daily email!

Test Your Vocabulary

Late Autumn 2018 Words of the Day Quiz

  • frosted-autumn-leaves
  • Which is a synonym of yahoo?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!