brain-stem vs neural structure

brain-stem and neural structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
brain-stem	Yes	No	No	No
neural structure	Yes	No	No	No

As nouns, neural structure is a hypernym of brain-stem; that is, neural structure is a word with a broader meaning than brain-stem:

brain-stem: the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus
neural structure: a structure that is part of the nervous system

brain-stem (noun)	neural structure (noun)
the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus	a structure that is part of the nervous system