tunic vs membrane

tunic and membrane both are nouns.

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

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

tunic: an enveloping or covering membrane or layer of body tissue
membrane: a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants

Other hypernyms of tunic include tissue layer.

tunic (noun)	membrane (noun)
any of a variety of loose fitting cloaks extending to the hips or knees	a thin pliable sheet of material
an enveloping or covering membrane or layer of body tissue	a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants