Complex sentence: A cotton mill is a factory housing powered spinning or weaving machinery for the production of yarn or cloth from cotton, an important product during the Industrial Revolution when the early mills were important in the development of the factory system.
Split into simpler sentences: A cotton mill is a factory that houses powered spinning or weaving machinery for the production of yarn or cloth from cotton. Cotton was an important product during the Industrial Revolution and cotton mills were important early examples of the factory system.