History of Manchester
According to Oxford University Press, Manchester derived its name from Mamucium, the Roman name for the 1st century-settlement and fort. Mamucium itself is a Latinised form of the Celtic meaning "breast-shaped hill".
Denton, Greater Manchester
Denton probably derives its name from Dane-town, an etymology supported by other place names in the area such as Danehead-bank and Daneditch-bourne. The word 'Dane' is itself derived from Anglo-Saxon "denu", "dene", "daenland", meaning a valley. So literally Denton means valley town.