A conurbation is a region comprising a number of cities, large towns, and other urban areas that, through population growth and physical expansion, have merged to form one continuous urban and industrially developed area. In most cases, a conurbation is a polycentric urban agglomeration, in which transportation has developed to link areas to create a single urban labour market or travel to work area.

The term "conurbation" was coined as a neologism in 1915 by Patrick Geddes in his book Cities In Evolution. He drew attention to the ability of the (then) new technology of electric power and motorised transport to allow cities to spread and agglomerate together, and gave as examples "Midlandton" in England, the Ruhr in Germany, Randstad in the Netherlands, New York-Boston in the United States, the Greater Tokyo Area and Taiheiyō Belt in Japan and NCR of Delhi in India.

A conurbation can be confused with a metropolitan area. As the term is used in North America, a metropolitan area can be defined by the Census Bureau or it may consist of a central city and its suburbs, while a conurbation consists of adjacent metropolitan areas that are connected with one another by urbanization.^{[clarification needed][citation needed]} Internationally, the term "urban agglomeration" is often used to convey a similar meaning to "conurbation".^{[clarification needed]} A conurbation should also be contrasted with a megalopolis, where the urban areas are close but not physically contiguous and where the merging of labour markets has not yet developed.