The document discusses definitions of rural and urban settlements. It states that while definitions of cities vary, some key characteristics of urban areas are large populations, tall buildings located close together, and economies focused on secondary and tertiary sectors like industry and services. The document also outlines several common functions of cities, including residential, commercial, industrial, tourist, political/administrative, and cultural/religious roles. It finally describes different patterns of urban design like grids, linear, radial, and irregular plans as well as components of urban structure like city centers, peri-urban areas, and outskirts.