alkylammonium
/ˌalkʌɪləˈməʊnɪəm/ /ˌalkɪləˈməʊnɪəm/Chemistry
noun
A cation which can be regarded as a derivative of ammonium (NH4 +) in which one or more hydrogen atoms (often, all four) have been replaced by alkyl groups. Usually attributive.
Origin
Late 19th century; earliest use found in Journal of the American Chemical Society. From alkyl + ammonium.