Tyranny is the technical form, although a noun would be a dictator. Synonym could be domination. Not sure exactly which word you're looking for, but hope this helps!
I think you are looking for a work for it - and this word is "megalopolis"
Some examples of a megalopolis are:
A Taiheyo belt in Japan (with Tokio and Osaka)
Northeast Megalopolis with New York and Boston
Yangze River Delta in China
Answer:
he taught millions to read, but no one to sin - Noah Webster
