What is the definition of imperialist countries?

A person who believes in expanding a nation's authority by territorial gains or by creating economic and political authority and spheres of influence over other nations. These people would have supported the gaining of the Philippines, Cuba, and the Panama Canal project. Theodore Roosevelt and many others were a major contributor to imperialistic views. Perhaps the first imperialists were Europeans. Their world-wide colonial empires were built on almost the same definition of Imperialism. The term of spheres of influence also is attached to imperialism.

-Amanda