lens nucleus vs structure

lens nucleus and structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
lens nucleus	Yes	No	No	No
structure	Yes	No	Yes	No

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

lens nucleus: the central structure of the lens that is surrounded by the cortex
structure: a particular complex anatomical part of a living thing and its construction and arrangement

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

lens nucleus (noun)	structure (noun)
the central structure of the lens that is surrounded by the cortex	a thing constructed; a complex entity constructed of many parts
	the manner of construction of something and the arrangement of its parts
	a particular complex anatomical part of a living thing and its construction and arrangement
	the complex composition of knowledge as elements and their combinations
	the people in a society considered as a system organized by a characteristic pattern of relationships

lens nucleus (verb)	structure (verb)
	give a structure to