MIDRIFF
diaphragm, midriff
(noun) (anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration
middle, midriff, midsection
(noun) the middle area of the human torso (usually in front); “young American women believe that a bare midriff is fashionable”
Source: WordNet® 3.1
Etymology
Noun
midriff (plural midriffs)
The middle section of the human torso, from below the chest to above the waist
Source: Wiktionary
Mid"riff, n. Etym: [AS. midhrif; midd mid, middle + hrif bowels,
womb; akin to OFries. midref midriff, rif, ref, belly, OHG. href
body, and to L. corpus body. See Corpse.] (Anat.)
Definition: See Diaphragm, n., 2.
Smote him into the midriff with a stone. Milton.
Source: Webster’s Unabridged Dictionary 1913 Edition