tissue layer vs midriff

tissue layer and midriff both are nouns.

Word	Noun	Adjective	Verb	Adverb
tissue layer	Yes	No	No	No
midriff	Yes	No	No	No

As nouns, midriff is a hyponym of tissue layer; that is, midriff is a word with a more specific, narrower meaning than tissue layer:

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

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