A global city, also known as a world city, is a prominent centre of trade, banking, finance, innovation, and markets.
The term "global city", as opposed to megacity, was coined by Saskia Sassen in a seminal 1991 work.
Whereas "megacity" refers to any city of enormous size, a global city is one of enormous power or influence. Global cities, according to Sassen, have more in common with each other than with other cities in their host nations.