Real Property Definition has many variances depending on where you look so its best to ask a lawyer if you have a specific question. However in one interpretation from a Real Estate license school "it is usually considered land and anything affixed, incidental or appurtenant to it, and anything considered immovable under the law. Land, buildings, and other immovable property permanently attached thereto.

Again we advise talking to a lawyer to get a more specifc perspective based on your situation and region.