Used in only two books of the Bible, there's some dispute today over its precise translation.
"Selah" appears 74 times in the Bible: three times in the minor prophet Habakkuk and seventy-one times in Psalms. It is usually found at the end of a verse, though in Psalms 3, 24, and 46, it's found at the very end of the psalm.
It is generally understood today as mark in the text indicating a musical interlude, which is reasonable considering that the Psalms were originally set to music. Other modern translators believe it directs the reader to stop and reflect or listen. Some ancient commentators translated it as "always". It's possible that it is related to the Hebrew word "calah" which means "to hang". Calah, to ancient Hebrew speakers of the Biblical era, would bring weighing an object in a hanging scale. Though selah may be instructing us, as Bible readers, to pause for a musical interlude, to stop and listen, or to take a moment to consider and weigh the words we just read, our reaction should be the same.
Psalm 32:7 You are my hiding place; You preserve me from trouble; You surround me with songs of deliverance. Selah.