layer vs complex body part

layer and complex body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
layer	Yes	No	Yes	No
complex body part	Yes	No	No	No

As nouns, complex body part is a hypernym of layer; that is, complex body part is a word with a broader meaning than layer:

layer: thin structure composed of a single thickness of cells
complex body part: a particular complex anatomical part of a living thing and its construction and arrangement

Other hypernyms of layer include anatomical structure, bodily structure, body structure, structure.

layer (noun)	complex body part (noun)
thin structure composed of a single thickness of cells	a particular complex anatomical part of a living thing and its construction and arrangement
a hen that lays eggs
single thickness of usually some homogeneous substance
an abstract place usually conceived as having depth
a relatively thin sheetlike expanse or region lying over or under another

layer (verb)	complex body part (verb)
make or form a layer