What is a core country?

A core country has to deal with something called world systems theory/world systems analysis. World system is a view of the global economic system as one divide between certain industrialized nations that control wealth and developing countries that are controlled and exploited. In this theory, there are three diffrent categories of countries: Core, Semiperiphery, and Periphery. Core countries are you're industrialized nations that tend to have the largest GDP (gross domestic product); some of the countries included as core countries are: Canada, France, Germany, Japan, the UK, and the united states. Semiperiphery nations include: China, India, Ireland, Mexico, Pakistan, and Panama. Periphery nations would include: Afghanistan, Bolivia, Chad, Dominican Republic, Egypt, Haiti, Philippines, and Vietnam. Periphery countries are basically third world countries. And semiperiphery countries are ones that are transitioning from Periphery to Core. World systems theory views the development of countries as a natural process where one nation transitions from periphery, to semiperiphery, to core. Core countries are more powerful and exploit the lesser nations for labor and resources. I hope that this helps out.