<p><strong>Noun</strong></p><ul><li>Hydrogen peroxide, H₂O₂ or H–O–O–H.</li><li>A compound containing the bivalent group –O₂–, derived from hydrogen peroxide, as sodium peroxide, Na₂O₂, or dimethyl peroxide, C₃H₆O₂.</li><li>The oxide of an element that contains an unusually large amount of oxygen.</li></ul>