abdominal

adjective

1. of, in, on, or for the abdomen: abdominal wall; abdominal pains.

noun

2. Usually abdominals. Informal. the abdominal muscles.

adj.

1550s, from medical Latin abdominalis, from abdomen (genitive abdominis); see abdomen.

1. In vertebrates, the portion of the body between the thorax and pelvis, containing the stomach, intestines, liver, and other organs. In mammals, the abdomen is separated from the thorax by the diaphragm.
2. In arthropods, the last, most posterior segment of the body.