What does oxidise mean?
To oxidise is to cause a substance to combine chemically with oxygen or to undergo that change naturally. The process is especially associated with the gradual deterioration of metals: iron rusts, copper develops a green surface layer, and silver blackens when exposed to air and moisture. In technical contexts, oxidising describes any reaction in which electrons are removed from a substance or its oxidation state increases. The verb can therefore be transitive, as in “heat oxidises the copper,” or intransitive, as in “the oil oxidises when stored for long periods.” British English uses “oxidise,” while American English normally uses “oxidize.” The word is useful in chemistry and also in discussions of preservation, corrosion, food storage, and materials science because it identifies a broad chemical process rather than simply naming a visible result such as rust.
verbTo combine chemically with oxygen, especially by adding oxygen to a substance. It can also be used intransitively for a substance that undergoes this chemical change.
- To combine a substance with oxygen or cause it to undergo oxidation.
- To undergo oxidation, especially through exposure to air, moisture, or another oxidising agent.
"Exposure to air can oxidise the surface of the metal."
"Copper gradually oxidises when exposed to moist air."
"The chemical process oxidises the metal and produces a protective coating."
The name of this process preserves the Greek roots for “sharp” and “sour,” because oxygen was once known as the acid-forming element.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does oxidise come from?
The verb was formed in the 19th century from “oxide” with the suffix “-ise.” “Oxide” comes through French from Greek oxys, combining with the suffix -idēs, and ultimately relates to the same roots found in “oxygen” and “acid.” The spelling with “-ize” became standard in American English, while British usage generally preferred “-ise.”
Related word forms
How oxidise is actually used
In British English, “oxidise” is the usual form; “oxidize” is standard in American English. The word is chiefly technical or scientific, although it is also used in general descriptions of rusting, tarnishing, and deterioration caused by oxygen. The spelling “oxydise” is obsolete.
Easily confused with oxidise
Oxidise is the standard British spelling, while oxidize is the standard spelling in American English.
Oxidise is a verb describing a chemical process, whereas oxide is a noun for a compound formed when another substance combines with oxygen.