midriff

The middle outer portion of the front of the human body, extending roughly from just below the breast to the waistline.

The diaphragm. See cut at diaphragm.

See diaphragm, n., 2.

The middle part of the front of the body, from the waist to the chest.

That part of a garment, especially a dress or bodice, that covers the midriff{2}.

The mid section of the human torso, from below the chest to above the waist

the middle area of the human torso (usually in front)

(anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration