interbrain vs betweenbrain

interbrain and betweenbrain both are nouns.

Word	Noun	Adjective	Verb	Adverb
interbrain	Yes	No	No	No
betweenbrain	Yes	No	No	No

As nouns, interbrain and betweenbrain are synonyms defined as:

interbrain and betweenbrain: the posterior division of the forebrain; connects the cerebral hemispheres with the mesencephalon

Other synonyms of interbrain include diencephalon, thalmencephalon.

interbrain (noun)	betweenbrain (noun)
the posterior division of the forebrain; connects the cerebral hemispheres with the mesencephalon	the posterior division of the forebrain; connects the cerebral hemispheres with the mesencephalon