name of a Germanic tribe or confederation from the Elbe River region that in late Roman times settled along the upper Rhine in Alsace and part of Switzerland, from Proto-Germanic *Alamanniz, probably meaning "all-man" (see all + man (n.)) and likely denoting a coalition or alliance of tribes rather than a single group.
But on another theory perhaps meaning rather "foreign men" (compare Allobroges, name of a Celtic tribe in what is now Savoy, in Latin literally "the aliens," in reference to their having driven out the original inhabitants), in which case the al- is cognate with the first element in Latin alius "the other" and English else.
The defeat of the Alemanni by a Frank-led army at Strasburg in 496 C.E. led to the conversion of Clovis and the rise of Frankish political power. The Alemanni were absorbed into the Frankish Kingdom in 796. Not historically important, but through proximity and frequent conflict with the Franks their name became the source of French Allemand, the usual word for "German, a German," and Allemagne "Germany." In modern use, Alemannish, Alemannic refers to the dialects of modern southwestern Germany; Alamannic refers to the ancient tribes and their language.