The belly of a blade is the curved part of a blade. A belly makes a knife especially good at slicing. A belly also makes for a less sharp point which means the knife blade is not as good for piercing cuts. When you are choosing a blade with a belly, make sure that you will be using it more for slicing than piercing. The Kershaw Blur pictured to the side is a perfect example of a blade with a belly. This would be considered an average sized belly. The Blur is great for slicing style cuts.