Amen! ~ where did the Amen word originate?

O.E., from L.L. amen, from Gk. amen, from Heb., "truth," used adverbially as an expression of agreement (e.g. Deut. xxvii.26, I Kings i.36; cf. Mod.Eng. verily, surely, absolutely in the same sense), from Sem. root a-m-n "to be trustworthy, confirm, support." Used in O.E. only at the end of Gospels, otherwise translated as So�lic! or Swa hit ys, or Sy! As an expression of concurrence after prayers, it is recorded from early 13c.