Is america an empire and explain why?

In a way it is, but also it isn't. The definition of Empire is: a group of states or countries under a single supreme authority. America is a group of states, and technically it is under one supreme authority. (The president) But, there is also the branches of government, supreme count, congress, and everything else that makes up America's government. Usually when you think of an empire, it is a country or nation trying to expand or take over. America isn't doing that. I would say technically it is, because it is a group of states under a supreme authority...