hall vs mansion house

hall and mansion house both are nouns.

Word	Noun	Adjective	Verb	Adverb
hall	Yes	No	No	No
mansion house	Yes	No	No	No

As nouns, hall and mansion house are synonyms defined as:

Other synonyms of hall include manse, mansion, residence.

hall (noun)	mansion house (noun)
a large building for meetings or entertainment	a large and imposing house
a large room for gatherings, receiving guests, or entertainment
an interior passage or corridor onto which rooms open
a college or university building containing living quarters for students
a large entrance or reception room or area
the large room of a manor or castle
a large and imposing house
a large building used by a college or university for teaching or research