megastate

plural megastates

1. A very large geopolitical state.

   […] the idea that a megastate like China or India might pass through a full-blown industrial revolution simply boggles the mind.

   2005, Paul Roberts, The end of oil: on the edge of a perilous new world

   1 more example

   At the dawn of the millennium, it is the fourth largest in the country, a megastate that was among those introducing new words into the American vernacular […]

   2008, Gary R. Mormino, Land of Sunshine, State of Dreams: A Social History of Modern Florida