medulla vs brain stem

medulla and brain stem both are nouns.

Word	Noun	Adjective	Verb	Adverb
medulla	Yes	No	No	No
brain stem	Yes	No	No	No

medulla (noun)	brain stem (noun)
the inner part of an organ or structure in plant or animal	the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus
lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata)
a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers