legionnaire (n.)youdaoicibaDictYouDict[legionnaire 词源字典]
1818, from French légionnaire, from légion (see legion). Legionnaires' Disease, caused by Legionella pneumophilia, was named after the lethal outbreak of July 1976 at the American Legion convention in Philadelphia's Bellevue Stratford Hotel. Hence Legionella as the name of the bacterium that causes it.[legionnaire etymology, legionnaire origin, 英语词源]