The Constitution guarantees private ownership of real estate. However, ownership rights are not absolute; others may exert claims against one's property.

Land - surface, all natural things attached to it, subsurface, and air above the surface

Real estate - land plus all permanently attached man-made structures, called improvements

Property - something that is owned by someone, and the associated rights of ownership; property is real or personal, tangible or intangible

Real property rights - the bundle of rights associated with owning a parcel of real estate. Foremost of these rights is the right of possession. 

An item may be real or personal property depending on the "attachment" criterion and other circumstances.

Fixtures - real property converted from personal property by attachment to real estate 

Trade fixtures - personal property items temporarily attached to real estate in order to conduct business; to be removed at some point 

Emblements - plants or crops considered personal property since human intervention is necessary for planting, harvesting 

Conversion - transforming real to personal property through severance, or personal to real property through affixing