di·​ox·​ide (ˌ)dī-ˈäk-ˌsīd How to pronounce dioxide (audio)
: an oxide (such as carbon dioxide) containing two atoms of oxygen in the molecule

Example Sentences

Recent Examples on the Web Atmospheric physicists William Happer and William van Wijngaarden have demonstrated that the current contribution of methane emissions to warming is only about a tenth of the small effect of carbon-dioxide emissions. WSJ, 19 Jan. 2023 An improvement to this process would lead to a substantial decrease in carbon-dioxide emissions. Stephen Witt, The New Yorker, 12 Dec. 2022 Carbon dioxide concentrations in 2021 were 415.7 parts per million (or ppm), methane at 1908 parts per billion (ppb) and nitrous oxide at 334.5 ppb. Steven Mufson, Anchorage Daily News, 26 Oct. 2022 Carbon dioxide concentrations have been increasing every year — and the rate of increase has been accelerating, as the graphic above shows. Tom Yulsman, Discover Magazine, 19 June 2019 Carbon dioxide emissions in 2020 fell by a record 1.9 billion tons as a result of strict Covid lockdowns that halted most air travel and disrupted daily lives. Denise Chow, NBC News, 11 Nov. 2022 But the iconic brand also brings some big hitters to the game: Silicon dioxide prevents clumping, and sodium citrate and soy lecithin help emulsify and enhance flavor. Ali Francis, Bon Appétit, 7 Dec. 2022 Carbon dioxide hangs around in the atmosphere for a long time. Elizabeth Kolbert, The New Yorker, 21 Nov. 2022 Quaise plans to join with power companies to feed steam to turbines in coal power plants, allowing these generators to be repurposed to create carbon-dioxide-free energy. Benoît Morenne, WSJ, 13 Nov. 2022 See More

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

Word History


International Scientific Vocabulary

First Known Use

circa 1847, in the meaning defined above

Time Traveler
The first known use of dioxide was circa 1847

Dictionary Entries Near dioxide

Cite this Entry

“Dioxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dioxide. Accessed 27 Jan. 2023.

Kids Definition


di·​ox·​ide (ˈ)dī-ˈäk-ˌsīd How to pronounce dioxide (audio)
: an oxide containing two atoms of oxygen in the molecule

Medical Definition


di·​ox·​ide (ˈ)dī-ˈäk-ˌsīd How to pronounce dioxide (audio)
: an oxide (as carbon dioxide) containing two atoms of oxygen in a molecule

More from Merriam-Webster on dioxide

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