corpus callosum vs commissure

corpus callosum and commissure both are nouns.

Word	Noun	Adjective	Verb	Adverb
corpus callosum	Yes	No	No	No
commissure	Yes	No	No	No

As nouns, commissure is a hypernym of corpus callosum; that is, commissure is a word with a broader meaning than corpus callosum:

corpus callosum: a broad transverse nerve tract connecting the two cerebral hemispheres
commissure: a bundle of nerve fibers passing from one side to the other of the brain or spinal cord

corpus callosum (noun)	commissure (noun)
a broad transverse nerve tract connecting the two cerebral hemispheres	a bundle of nerve fibers passing from one side to the other of the brain or spinal cord