What term refers to the old industrial zone and old housing zone combined?

The term that refers to the old industrial zone and old housing zone combined is the inner city. The inner city typically encompasses the central part of a city that has historically been the hub of industrial activities and residential living, often characterized by older buildings and infrastructure.

This area often reflects a city's historical economic activities, such as manufacturing and trade, which were prevalent in the past. As industrialization peaked, these zones developed with associated housing for workers, leading to a mixed landscape of industry and residential areas.

Understanding this concept is important as many inner city areas have undergone significant changes over time, including urban renewal projects, which can transform these neighborhoods. However, they often retain their historical character, which distinguishes them from suburban areas, rural areas, or metropolitan zones, each representing different aspects of urban and geographic development.