Wiktionary
n. (context chemistry English) Any of a class of organic compound formed by addition of an oxygen atom to an amine - R3N+-O-, but sometimes written R3N=O.
Wikipedia
An amine oxide, also known as amine-N-oxide and N-oxide, is a chemical compound that contains the functional group RN–O, an N–O bond with three additional hydrogen and/or hydrocarbon side chains attached to N. Sometimes it is written as RN→O or, wrongly, as RN=O.
In the strict sense the term amine oxide applies only to oxides of tertiary amines. Sometimes it is also used for the analogous derivatives of primary and secondary amines.
Examples of amine oxides include pyridine N-oxide, a water-soluble crystalline solid with melting point 62–67 °C, and N-methylmorpholine N-oxide, which is an oxidant.