residence vs mansion house

residence and mansion house both are nouns.

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

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

Other synonyms of residence include hall, manse, mansion.

residence (noun)	mansion house (noun)
the act of dwelling in a place	a large and imposing house
the official house or establishment of an important person (as a sovereign or president)
a large and imposing house
any address at which you dwell more than temporarily