tri·​ox·​ide (ˌ)trī-ˈäk-ˌsīd How to pronounce trioxide (audio)
: an oxide containing three atoms of oxygen

Examples of trioxide in a Sentence

Recent Examples on the Web It was used to describe the compound arsenic trioxide, which can be lethal at 100 milligrams, about one-fiftieth of a teaspoon. Veronique Greenwood, Discover Magazine, 30 Aug. 2013 When an adhesive containing this additive is heated appropriately, the acid decomposes into three gases: sulphur dioxide, sulphur trioxide and steam. The Economist, 28 May 2020 Instead the researchers only employed two differentiation agents: all-trans retinoic acid and arsenic trioxide. Philip Ball, Scientific American, 21 Apr. 2020 In the future, the photographer plans to test out more exotic thermites like bismuth trioxide and manganese dioxide. Wired, 31 Oct. 2019 Thanks to its central location, its reputation for manufacturing and an abundant supply of sulfur trioxide in the area, Ohio was the perfect location for Morrisoe to begin implementing his vision of scaling up his chemical company. Jessica Levy,, 7 June 2019 The report listed three other products — aluminum ingots, ammonium paratungstate and tungsten trioxide — that Hongxiang sold to North Korea and that the United States Commerce Department considers to have possible civilian and nuclear uses. Jane Perlez and Chris Buckley, New York Times, 20 Sep. 2016

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'trioxide.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


International Scientific Vocabulary

First Known Use

1863, in the meaning defined above

Time Traveler
The first known use of trioxide was in 1863

Dictionary Entries Near trioxide

Cite this Entry

“Trioxide.” Dictionary, Merriam-Webster, Accessed 25 Jun. 2024.

Medical Definition


tri·​ox·​ide (ˈ)trī-ˈäk-ˌsīd How to pronounce trioxide (audio)
: an oxide containing three atoms of oxygen
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