early 14c., "to lay claim to," from Latin acclamare "to cry out at" (in Medieval Latin "to claim"), from ad "to, toward" (see ad-) + clamare "cry out" (from PIE root *kele- (2) "to shout"). The meaning "to applaud" is recorded by 1630s. The spelling has been conformed to claim. Related: Acclaimed; acclaiming; acclamatory.