A townhouse is a style of housing where side-by-side homes share a common wall(s) with their neighbors. A townhome is typically multiple stories high.
The word townhome generally refers to the style of the home, not the form of ownership. In Seattle, a townhome may be classified as a single-family residence where the structure and land beneath it is owned by the homeowner. It may also be a condominium where the interior of the structure is owned by the homeowner and the exterior and land is owned in common with other homeowners in the homeowners association.