trioxide

American

[trahy-ok-sahyd, -sid] / traɪˈɒk saɪd, -sɪd /

noun

Chemistry.

an oxide containing three oxygen atoms, as As 2 O 3 .

trioxide British

/ traɪˈɒksaɪd /

noun

any oxide that contains three oxygen atoms per molecule

sulphur trioxide, SO3

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of trioxide

First recorded in 1865–70; tri- + oxide

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

trioxide

"It may be that in normal conditions phosphorus is bound up in another molecule such as phosphorus trioxide," explained Beiler.

From Science Daily ● Nov. 9, 2025

Both antimony trioxide and the suite of haloacetic acids have previously been recognized by state and federal agencies as hazardous substances.

From Salon ● Jan. 12, 2022

Sulfur trioxide forms slowly when heating sulfur dioxide and oxygen together, and the reaction is exothermic:

From Textbooks ● Feb. 14, 2019

In the form of arsenic trioxide, it can be used to treat acute promyelocytic leukemia, the book says.

From Washington Post ● Jun. 10, 2013

Compounds.—Bismuth forms four oxides, of which the trioxide, Bi2O3, is the most important.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 1 "Bisharin" to "Bohea" by Various

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023