Selah

Selah - The word סלה appears in Jewish prayers and in the Bible many times, mostly in the Book of Psalms and some in the Book of Habakkuk, in the "Prayer of Habakkuk" (chapter 3). The word appears mainly as an ending to a verse, and sometimes in the middle of it. Its exact meaning is disputed: some say that it expresses a certain content as a continuation of what was said before it, in the sense of "forever", or as confirmation and reinforcement such as "in truth". Others say that it is not part of the substantive content of the verse, but rather a kind of sign in poetry, to indicate raising the voice, etc. Per the first opinion it is a substitute for "Amen".

The Oxford Annotated Revised Standard Version, College Edition, describes "Selah" as "a liturgical direction," perhaps indicating that "there should be an instrumental interlude at this point in the singing of the psalm."