What does methoxy mean?
Methoxy denotes the chemical group –OCH₃, in which a methyl group is joined to an oxygen atom. It is encountered especially in organic chemistry, medicinal chemistry, and the systematic description of molecular structures. The term may function as a noun when referring to the group itself or as an adjective when describing a compound or substituent containing it. Its structural identity is important: in a methoxy group, the rest of the molecule is bonded to the oxygen, whereas in a methyl group, it is bonded directly to the carbon. Methoxy groups can influence a compound's solubility, electronic properties, and biological activity, so their presence is often significant in pharmaceutical and chemical research. Although “methoxy” is occasionally used alone in technical writing, expressions such as “methoxy group” and “methoxy substituent” are normally clearer in general scientific prose.
The univalent chemical group –OCH₃, attached to another atom through oxygen.
"Each ring carries a methoxy group."
Usually used in the phrase “methoxy group”; the plural “methoxys” is possible in technical writing, but “methoxy groups” is more natural in general prose.
Having, containing, or involving one or more –OCH₃ groups.
"The researchers synthesized a series of methoxy analogues."
Used chiefly in organic and medicinal chemistry.
The plural “methoxys” is possible when the shortened noun is used technically, but “methoxy groups” is the preferred natural form.
"Several methoxy groups occur along the backbone of the molecule."
A methoxy group is methyl on oxygen: CH₃O–.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does methoxy come from?
The word is formed by combining the chemical combining forms associated with methyl and oxy, the latter derived from oxygen. The compound form follows established organic-chemistry nomenclature and refers specifically to a methyl group attached through an oxygen atom. Its construction parallels related substituent names such as ethoxy and propoxy.
Related word forms
How methoxy is actually used
Chiefly a term in organic and medicinal chemistry. As a noun, it usually appears in the fixed phrase “methoxy group”; the pronunciation of the second syllable differs between British and American English.
Easily confused with methoxy
A methoxy group is –OCH₃ and connects through oxygen, whereas a methyl group is –CH₃ and connects through carbon.
Methoxy denotes an –OCH₃ group, while ethoxy denotes the related but larger –OC₂H₅ group.