A condominium and a townhome are both types of multi-unit properties, but they differ in ownership and maintenance structure. 

A condominium is a type of property in which an individual owns a specific unit within a larger building or complex. The individual unit owner has exclusive ownership of their unit and shared ownership of the common areas, such as hallways, elevators, and recreational facilities. The condominium association, made up of all the individual unit owners, is responsible for managing and maintaining the common areas and enforcing rules and regulations. 

A townhome, on the other hand, is a type of attached single-family home that typically shares one or more walls with adjacent units. Each townhome unit is individually owned, and the owner is responsible for the maintenance of their unit and the land directly around it. Townhome communities may also have shared amenities or facilities, but they are typically owned and maintained by a homeowners association (HOA) that is made up of all the individual townhome owners. 

In summary, the key differences between a condominium and a townhome are the ownership and maintenance structure. A condominium owner owns a specific unit within a larger complex and shares ownership of the common areas, while a townhome owner owns the entire unit and is responsible for the maintenance of their individual unit and the land surrounding it.