Uper means near, near, near something, proximity. Deepest meaning of upe is what is the most proximate thing to you? You yourself. Can't be anything nearer than that, the self. Nista, conviction, free from any doubt, beyond doubt, absolutely certain. Sat has three meanings: visherana, gati, avasadan. The primary meaning is gati,. Gati means the goal, to take you to the goal. Ava gaty means knowledge which takes you to brahman - not a physical journey.