midriff vs membrane

midriff and membrane both are nouns.

Word	Noun	Adjective	Verb	Adverb
midriff	Yes	No	No	No
membrane	Yes	No	No	No

As nouns, membrane is a hypernym of midriff; that is, membrane is a word with a broader meaning than midriff:

midriff: (anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration
membrane: a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants

Other hypernyms of midriff include tissue layer, muscle system, muscular structure, musculature.

midriff (noun)	membrane (noun)
(anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration	a thin pliable sheet of material
the middle area of the human torso (usually in front)	a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants