fundus vs anatomical structure

fundus and anatomical structure both are nouns.

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

As nouns, anatomical structure is a hypernym of fundus; that is, anatomical 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
anatomical structure: a particular complex anatomical part of a living thing and its construction and arrangement

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

fundus (noun)	anatomical 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