Origin: 1535–45; < Latinacclāmātiōn- (stem of acclāmātiō) a shouting, equivalent to acclāmāt(us) (past participle of acclāmāre; see acclaim, -ate1) + -iōn--ion
1540s, from L. acclamationem (nom. acclamatio, gen. acclamationis), from pp. stem of acclamare "shout approval or disapproval of, cry out at," from ad- "toward" + clamare "cry out" (see claim).