Belly
WordNet
noun
(1) The underpart of the body of certain vertebrates such as snakes or fish
(2) A protruding abdomen
(3) The region of the body of a vertebrate between the thorax and the pelvis
(4) The hollow inside of something
"In the belly of the ship"
(5) A part that bulges deeply
"The belly of a sail"
verb
(6) Swell out or bulge out