diencephalon vs betweenbrain

diencephalon and betweenbrain both are nouns.

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

As nouns, diencephalon and betweenbrain are synonyms defined as:

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

Other synonyms of diencephalon include interbrain, thalmencephalon.

diencephalon (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