1350-1400;Middle Englishconfederat < Late Latinconfoederātus (past participle of confoederāre to unite in a league), equivalent to con-con- + foeder- (stem of foedus) treaty (see fidelity) + -ātus-ate1
c.1370, from O.Fr. confédérer, from L.L. confoederatus, pp. of confoederare "to unite by a league," from con- "with, together" + foedus (gen. foederis) "a league" (see federal). Also used as a pp. adj. from late 14c., as a simple adj. from 1550s; meaning "of or belonging to the Confederate States of America" is from 1861. Used as a noun from 1540s (L.L. confoederatus also was used as a noun in its day).