di·​ox·​ide | \ (ˌ)dī-ˈäk-ˌsīd \

Definition of dioxide

: an oxide (such as carbon dioxide) containing two atoms of oxygen in the molecule

Examples of dioxide in a Sentence

Recent Examples on the Web

The result is that the U.S. has cut its carbon-dioxide output year after year without the aid of a carbon tax. David R. Henderson, WSJ, "A Nobel Economics Prize for the Long Run," 8 Oct. 2018 Air pollution has become an increasing problem in Germany, with nitrous dioxide causing over 10,000 premature deaths in 2016. David Grossman, Popular Mechanics, "First Hydrogen-Powered Trains Rolling in Germany," 19 Sep. 2018 For the three years straddling the 2015 Paris conference, carbon-dioxide emissions were more or less flat. Rupert Darwall, WSJ, "Defeat in the Air at the Climate Conference," 18 Dec. 2018 Some even suggested that the streaks were caused by seasonal carbon-dioxide frost. Chelsea Gohd, Space.com, "Wow! This Fresh Meteoroid Impact on Mars Triggered a Dusty Avalanche," 19 June 2018 The casing of each earbud is made out of scratch-proof zirconium dioxide, which sounds like the same ceramic material as used in RHA’s previous high-end pair, the CL1 Ceramic. Vlad Savov, The Verge, "RHA announces in-ear planar magnetic earphones with wireless option," 23 Aug. 2018 Other pollutants are in the air, including sulphur dioxide, formed by fossil fuel combustion, carbon monoxide and nitrogen dioxide, formed by emissions from motor vehicles, gas heaters and cigarette smoke, and ground-level ozone, formed by smog. Christine Clarridge, The Seattle Times, "Seattle air quality readings vary. Here’s how to interpret them.," 21 Aug. 2018 Australia’s Commonwealth Scientific and Industrial Research Organisation, or CSIRO, has spent a decade developing a supersonic nozzle to make magnesium metal with 70% fewer carbon-dioxide-equivalent emissions. Rhiannon Hoyle, WSJ, "Miners Test Greener Ways to Dig," 16 July 2018 The spaceflight forced the astronauts to make critical repairs to the craft's carbon-dioxide removal system. Carie Lemack, Space.com, "Apollo 13's Importance: How Failure Can Lead to Great Success," 31 May 2018

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.

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First Known Use of dioxide

circa 1847, in the meaning defined above

History and Etymology for dioxide

International Scientific Vocabulary

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Statistics for dioxide

Last Updated

4 Feb 2019

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Time Traveler for dioxide

The first known use of dioxide was circa 1847

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English Language Learners Definition of dioxide

chemistry : a molecule that has two atoms of oxygen and one atom of another element (such as carbon)


di·​ox·​ide | \ (ˈ)dī-ˈäk-ˌsīd \

Medical Definition of dioxide

: an oxide (as carbon dioxide) containing two atoms of oxygen in a molecule

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More from Merriam-Webster on dioxide

Rhyming Dictionary: Words that rhyme with dioxide

Nglish: Translation of dioxide for Spanish Speakers

Britannica English: Translation of dioxide for Arabic Speakers

Comments on dioxide

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


to deny responsibility for

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