Townhomes come in many shapes and sizes ... It might surprise you to learn that townhomes are a type of structure which are held in various forms of ownership. Here's a few pictures and facts about townhomes which illustrate the types of townhomes.
A townhome is a multi-story structure which shares 1, 2 or 3 walls with another home. If one side wall (other than the front wall) isn't attached to another home it's called an End-Unit. If both side walls are shared with other homes, it's called an Interior Unit. Generally these types of townhomes would have some land as their rear yard. End-Units generally have additional windows and land on their open side.
A townhome may share a back wall with another unit. This townhome structure might be called a back-to-back unit. An interior back-to-back unit would only have windows on it's front side. Since these units are back-to-back, they would not have a rear yard.
A townhome may sit on top of another townhome. Individuals in this townhome structure would be referred to as 'piggy-back' townhomes with the upper and lower units. Sometimes the lower unit hosts garages for both units. Consequently, the upper unit would have considerably more interior floor space. If the units don't have garages, they may have some land assigned as their rear yard. Since both the upper and lower units stand over the same plot of land, they are very likely to be under condominium ownership.
A townhome structure could also be located at the ends of a garden style building and have a separate direct entrance. Since these units are part of a multi-level garden style building, it's unlikely that they would have an assigned rear yard ... And they are part of a garden style building, they might be under condominium ownership.
The term 'townhome' refers to a home's structure rather than it's legal ownership. In Northern Virginia, townhomes may be deeded under Fee Simple, Condominium or Cooperative ownership. Under Fee Simple ownership, the unit owner holds title to the structure and the land it sits on. Under Condominium ownership, the unit owner holds title to the interior of the unit and a fraction of the Condominium Association. Under Cooperative ownership, ownership only inlvolves a fraction of the Cooperative Association and the assigned the use of a particular unit.