https://archive.org/details/citiesinevolutio00gedduoft/page/n9/mode/1upPatrick Geddes coined the term in his book Cities In Evolution (1915). He drew attention to the ability of the new technology at the time 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, and the Northeastern Seaboard in the United States.
https://en.wikipedia.org/wiki/Conurbation
https://en.wikipedia.org/wiki/Patrick_Geddes