Definition of "mansion house" [mansion house]

• The house in which one resides; specifically, in London and some other cities, the official residence of the Lord Mayor. (noun)
• A large and imposing house. (noun)

Gnu Collaboartive International Dictionary of English: licensed under The Code Project Open License (CPOL)

• "WILLIAM JAY, whose residence is chiefly at his country seat in Westchester county, in the mansion house of his venerable and venerated father, Gov."