retina vs tissue layer

retina and tissue layer both are nouns.

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

As nouns, tissue layer is a hypernym of retina; that is, tissue layer is a word with a broader meaning than retina:

retina: the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve
tissue layer: a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants

Other hypernyms of retina include membrane.

retina (noun)	tissue layer (noun)
the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve	a pliable sheet of tissue that covers or lines or connects the organs or cells of animals or plants