dioxide

American  

[dahy-ok-sahyd, -sid] / daɪˈɒk saɪd, -sɪd /

noun

Chemistry.

1. an oxide containing two atoms of oxygen, each of which is bonded directly to an atom of a second element, as manganese dioxide, MnO 2 , or nitrogen dioxide, NO 2 .

---

dioxide British  

/ daɪˈɒksaɪd /

noun

1. any oxide containing two oxygen atoms per molecule, both of which are bonded to an atom of another element

2. another name for a peroxide

---

dioxide Scientific  

/ dī-ŏk′sīd /

1. A compound containing two oxygen atoms per molecule.

---

Etymology

Origin of dioxide

First recorded in 1840–50; di- ¹ + oxide

Example Sentences

Together, the methane and carbon dioxide measurements point to a formation history that differs significantly from that of most comets that originated around our Sun.

From Science Daily • Jun. 4, 2026

Not only do they store up to five times more carbon dioxide than land-based forests, but their tangled roots can also slow down waves and protect coastal communities from storm surges and tsunamis.

From BBC • Jun. 4, 2026

Perhaps the best-known examples of fermentation are in baking and brewing, where yeast breaks down sugar into ethanol and carbon dioxide.

From BBC • Jun. 4, 2026

Alternatives made from used cooking oil, cover crops and even captured carbon dioxide would have eased pressures on the beleaguered industry—if only there had been enough to go round.

From The Wall Street Journal • Jun. 2, 2026

Even worse, burning coal produces air pollutants, including sulfur dioxide and nitrogen oxide, that are real threats to human health.

From "Meltdown" by Deirdre Langeland