Final answer:
The item that becomes real property when attached to land or a building is termed a fixture, which reverts to personal property upon removal. This transformation process is known as annexation when attaching and severance when detaching.
Step-by-step explanation:
The item being described is known as a fixture. A fixture is personal property that has been attached to land or a building and becomes real property. However, if this item is removed from the real property, it is then classified as personal property. The process of converting personal property into real property by attaching it to the real estate is called annexation, and the reverse process—converting real property to personal property—is called severance.
In early societies, like the Mesopotamian cities, the concept of property extended to various domains, with items ranging from land, animals, material objects, and even slaves. However, in modern legal contexts, property rights and definitions have evolved, and the distinction between personal and real property is typically a matter of the item's attachment and adaptability to the real property.