What does the word AMEN mean and where does it say the meaning in the bible if anywhere?? thank you.?

The Hebrew definition of the word, "Amen," is "so be it." In Isaiah 65:16 the Lord is called "the God of truth"; which in the original Hebrew means, "the God of Amen." This is Isaiah’s way of saying that the Lord is the One who can always be relied on. Jesus is given the same title; "the Amen, the Faithful and True Witness" (Rev. 3:14) for the same reason.