calcium oxide


Definition of calcium oxide

: a caustic solid CaO that is white when pure and that is the chief constituent of lime

Examples of calcium oxide in a Sentence

Recent Examples on the Web The gates, entrances and grounds of many farms were covered in snowy layers of calcium oxide, a disinfectant. Washington Post, "Fears grow in South Korea as tests confirm more swine fever," 25 Sep. 2019 The primary ingredient in concrete is calcium oxide, which is taken from limestone (CaCO3)—and that leaves CO2 as a byproduct. Scott K. Johnson, Ars Technica, "Splitting water to make cement could clean up a dirty industry," 17 Sep. 2019 There the calcium carbonate is heated to 900°C to release pure carbon-dioxide gas ready for capture, and calcium oxide. The Economist, "Extracting carbon dioxide from the air is possible. But at what cost?," 7 June 2018 On top of the harling went several coats of limewash, a mixture of water and calcium oxide. David Kamp, Vanities, "How Jeremy Irons Rescued and Restored a 15th-Century Irish Castle," 22 Sep. 2017 The concrete is made of quicklime, or calcium oxide, and volcanic ash. Erin Blakemore, Smithsonian, "Why Ancient Roman Concrete Is So Strong," 5 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'calcium oxide.' 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 calcium oxide

1859, in the meaning defined above

Keep scrolling for more

Learn More about calcium oxide

Time Traveler for calcium oxide

Time Traveler

The first known use of calcium oxide was in 1859

See more words from the same year

Statistics for calcium oxide

Cite this Entry

“Calcium oxide.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2021.

More from Merriam-Webster on calcium oxide Encyclopedia article about calcium oxide

Comments on calcium oxide

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


Test Your Vocabulary

Slippery Words Quiz—Changing with the Times

  • ducreux self portrait yawning
  • What is an earlier meaning of nice?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!


Anagram puzzles meet word search.

Love words? Need even more definitions?

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