Which term refers to a neighborhood where homes are built close together and share walls?

The correct answer is townhouse. A townhouse is a type of residential building that is typically part of a row of similar structures, where each home shares one or two walls with neighboring homes. This design allows for efficient use of space and typically provides a more compact living arrangement.

In contrast, a detached house stands alone and does not share any walls with other residences, offering more privacy but often requiring more land area. A duplex refers specifically to a building divided into two separate living units, which may or may not share walls, but is generally recognized as a specific arrangement compared to a townhouse. An apartment complex consists of multiple individual apartments within a larger building or group of buildings, where units are usually stacked vertically and not typically referred to as homes that share walls in the same sense as townhouses. This context solidifies the notion that a townhouse is the appropriate term for homes built close together and sharing walls.