___________ include privacy walls, boundary-marking walls on property, and town walls. These intergrade into fence.

Boundary walls include privacy walls, boundary-marking walls on property, and town walls. These intergrade into fences. The conventional differentiation is that a fence is of minimal thickness and often open in nature, while a wall is usually more than a nominal thickness and is completely closed, or opaque. More to the point, an exterior structure of wood or wire is generally called a fence—but one of masonry is a wall.