“Each city may have its own defined term,” said G. Adam Baugh, a land use and zoning attorney with the law firm Withey Morris in Phoenix. “Infill is generally the development of vacant or under-utilized parcels within existing urban areas that are already largely developed around it,” he said. “Most communities have vacant land, which for various reasons, has been passed over in the normal course of growth and build-out. While this applies to both urban and suburban areas, it is more common in urban areas where there is new neighborhood renewal in older parts of the city.”