Organic compounds containing the group –O– in their molecules. Examples are dimethyl ether, CH3OCH3, and diethyl ether, C2H5OC2H5 (see ethoxyethane). They are volatile highly flammable compounds made by dehydrating alcohols using sulphuric acid.
https://www.acdlabs.com/iupac/nomenclature/79/r79_227.htm Information about IUPAC nomenclature