Treated as plural. A confederation of Germanic peoples originally occupying southwest Germany between the Rhine, the Main, and the Danube, and later parts of Switzerland and Alsace.
Old English; earliest use found in Orosius' History. From post-classical Latin Alemanni, plural noun (4th or 5th cent. in Jerome; from 9th cent. in British sources; also Alamanni; compare Hellenistic Greek Ἀλαμανοί, plural noun (3rd cent. a.d.)) from an unattested Germanic compound from the Germanic base of all + the Germanic base of man.