Urban concentration: Tendency of people and activities to cluster together
Urban decentralization: Flight of people and activities from the centre of the city.
Urban Succession: Completed replacement of one kind of people or activity by another.
Metropolis: An urban area including a city and its surrounding suburbs.
Urban ecological processes: It is process whereby spatial distribution of people and activities change.
Gravity model: The number of migrants or other persons attracted to a place is directly related to the population size of the destination and inversely related to the distance between the origin and destination.
Region: The area that is remarkably different from other areas in terms of some specific criteria.
Rank size rule: The regularity in the population sizes of cities in a country or region such that the largest city is twice the size of second largest city, three times to the third largest city, four times to the fourth largest urban centre and so on. This rule was given by Zipf.
Urban renewal: The projects for the removal of deteriorated sections from the city to make it more attractive for business activities are called urban renewal. It includes removal of the poor, slum dwellers on racial and class lines. The new housing is out of the financial reach of the poor. Urban renewal therefore is often unfair irrespective of whatever the measures undertaken for the rehabilitation of the displaced people.