Final answer:
The rapid growth of cities during the industrial revolution was referred to as urbanization, which was driven by industrialization and immigration, leading to massive population shifts from agricultural rural areas to urban centers.
Step-by-step explanation:
The rapid growth of cities during the industrial revolution was called urbanization. This phenomenon occurred as a results of transformative technological advancements and the subsequent increase in factory-based production. As cities like Manchester, New York, and London experienced explosive growth due to their proximity to resources and opportunities for employment in the emerging industries, populations shifted massively from rural to urban areas. This was seen in the rise of Manchester's population from 20,000 in 1750 to 400,000 by 1850. Similarly, London's population increased from 550,000 in the mid-1670s to 7 million by the early 1900s. Urbanization was tightly interconnected with industrialization and immigration, as the need for a larger workforce prompted people to move toward urban centers where technological advances made factory work essential. Despite the opportunities provided by life in these industrial cities, rapid urbanization also led to difficult living conditions, including overcrowding and poor sanitation.