braincase vs brainpan

braincase and brainpan both are nouns.

Word	Noun	Adjective	Verb	Adverb
braincase	Yes	No	No	No
brainpan	Yes	No	No	No

As nouns, braincase and brainpan are synonyms defined as:

Other synonyms of braincase include cranium.

braincase (noun)	brainpan (noun)
the part of the skull that encloses the brain	the part of the skull that encloses the brain