You're probably referring to the gallbladder. The gallbladder sits under the liver and produces/stores extra bile, it is an unessential organ of the body and can be removed without consequences.
stomach
The stomach.
starts in you stomach.
The body or body region.
stomach
the stomach
its stomach
torso
· sternum · stomach
Stomach or Teeth
the body of the stomach
Probably your stomach but if your asking what's the biggest inside part of your body,I don't know.