Definition
When you miss the green on the approach shot, you'll have a chip shot. If you hit that chip shot close to the hole and then make the putt, it's called an "up and down". Another term for this is "scrambling". You might hear someone say, "Wow, he really scrambled to make that par", which means the golfer hit a challenging pitch shot or chip shot and then made a good putt.
Usage
Nice up and down!