What term describes an interest in real property that consists of a separate interest in a unit and an undivided interest in common areas?

The term that describes an interest in real property consisting of a separate interest in a unit along with an undivided interest in common areas is a condominium. In a condominium, each owner has individual ownership of their specific unit, which allows for personal modifications and uses, while simultaneously possessing a shared interest in the common areas of the property, such as hallways, recreational facilities, and land. This unique ownership structure combines both private and communal aspects, making it distinct from other forms of housing.

In contrast, an apartment typically refers to a rental unit within a building where individuals do not own the space but pay rent to a landlord. A duplex is a type of residential building that consists of two separate living units, often under one roof, and does not include the shared ownership aspect found in a condominium. A townhouse, while also a form of multi-family housing, typically does not involve a shared undivided interest in common areas to the same extent as a condominium and is instead characterized by individual ownership of the unit and sometimes shared responsibilities for external maintenance.