The belly of a person or animal is their stomach or abdomen. In British English, this is an informal or literary use. She laid her hands on her swollen belly You'll eat so much your belly'll be like a barrel. see also beer belly, pot belly = stomach, tummy
If a company goes belly up, it does not have enough money to pay its debts. I really can't afford to see this company go belly up. = go bust. belly out bellied bellying bellies to fill with air and become rounder in shape
the underpart of the body of certain vertebrates such as snakes or fish a protruding abdomen the hollow inside of something; "in the belly of the ship"