If the front part of your body below your waist feels uncomfortable because you are feeling worried or frightened, you can refer to it as your stomach .
1. an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion
2. the region of the body of a vertebrate between the thorax and the pelvis
3. an inclination or liking for things involving conflict or difficulty or unpleasantness;
"he had no stomach for a fight"
4. an appetite for food;
"exercise gave him a good stomach for dinner"
Verb
1. bear to eat;
"He cannot stomach raw fish"
2. put up with something or somebody unpleasant;
"I cannot bear his constant criticism""The new secretary had to endure a lot of unprofessional remarks""he learned to tolerate the heat""She stuck out two years in a miserable marriage"