belly
noun
A belly is the round part of your body located between your chest and your legs. It's where you have your stomach and other organs. It's also called your tummy.
Example
1. My son loves to rub his hands over my growing belly when he's feeling sleepy.
2. I could feel my stomach tightening with each wave of nausea that rolled through my belly.
3. After overeating, my belly was so full I thought it was going to burst.