fundus vs body structure

fundus and body structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
fundus	Yes	No	No	No
body structure	Yes	No	No	No

As nouns, body structure is a hypernym of fundus; that is, body structure is a word with a broader meaning than fundus:

fundus: (anatomy) the base of a hollow organ or that part of the organ farthest from its opening
body structure: a particular complex anatomical part of a living thing and its construction and arrangement

Other hypernyms of fundus include anatomical structure, bodily structure, complex body part, structure.

fundus (noun)	body structure (noun)
(anatomy) the base of a hollow organ or that part of the organ farthest from its opening	a particular complex anatomical part of a living thing and its construction and arrangement