What term describes the boundary between a city and the countryside?

The term that describes the boundary between a city and the countryside is "urban fringe." This area represents the transition zone where urban and rural land uses blend together. In the urban fringe, you can often find a mix of residential developments, light industrial activities, and agricultural land, which reflects the influence of the nearby city while still maintaining elements of rural life.

The urban fringe is significant in urban geography because it illustrates how cities expand and the pressures of urbanization on surrounding rural areas. This region can experience various socio-economic dynamics, such as population growth and changes in land use, as cities extend their reach outward.

The other terms do not accurately describe this boundary. The term "rural-urban fringe" may initially seem potentially correct, but it is less commonly used in geographical literature, and the preferred term is "urban fringe." "Concentric zone" refers to a model that depicts urban land use in concentric circles, which doesn't directly address the city-countryside boundary. "Suburban border" might suggest a border of suburban developments, but it doesn't encompass the broader concept of the transition between urban and rural areas. Therefore, the urban fringe is the most appropriate and widely recognized term for this boundary.