Mansion
Part of speech: noun
Definition: A large house or building. A luxurious flat (apartment). A house provided for a clergyman; a manse. A stopping-place during a journey; a stage. An astrological house; a station of the moon. One of twenty-eight sections of the sky. Any of the branches of the Rastafari movement (after John 14:2, "In my Father's house are many mansions").
Example sentence: To get over my divorce, I got a prescription to live at the Playboy Mansion for a while.
Estate
Part of speech: noun
Definition: An area on land under single ownership.The nature and extent of a person's interest in, or ownership of, land.All that a person owns, whether real or personal property.The property of a deceased person.A group of buildings built together as a single development on a designated area of land. (w:Housing estate)A body style for cars, popular with families, which has an enclosed area where the boot or trunk would be on a sedan / saloon.An estate car.A major social class or order of persons regarded collectively as part of the body politic of the country and formerly possessing distinct political rights (w:Estates of the realm)