R&R. In a nice world, it means rest and relaxation, which sounds beyond heavenly right now. In the writing world, it means something completely different, but also hopeful - revise and resubmit. This is when a publisher or agent sends it back to you asking you to change something (or many somethings) and resubmit. It's not a guarantee that if you do all these changes, they will accept it, but there's a pretty dang good chance.
When you are submitting your work, trying to find a home for this little piece of your soul, a revise and resubmit is an exciting step in the right direction. Even if you don't decide to do it, take a good look at what they're asking -- could it make your story better? This business is subjective, so what you change has to feel good to you.