abdomen：part of the body below the chest and diaphragm, containing the stomach. 腹部
Abdominal (adj) 腹部的
an abdominal operation 腹部手术
belly：(口)front of the human body from the waist to the groin；belly 肚子，胃
with an empty belly 空着肚子
in the belly of a ship 在船腹里
belly out(动词用法)：鼓涨，凸出
The wind bellied out the sails