Wiktionary
n. A powerful, privileged social class.
Wikipedia
Overclass is a recent and pejorative term for the most powerful group in a social hierarchy. Users of the term generally imply excessive and unjust privilege and exploitation of the rest of society.
Perhaps the most commonly agreed-upon "overclass" consists of leaders in international business, finance and the war industry.
The influence of the actions by the overclass have been rigorously studied, particularly with regards to notions of intersections between the overclass and specific races. Most notable of these racial overclasses is the NEWBO, or NEW Black Overclass in America.
The word is fairly recent: the Oxford English Dictionary included it only in December 2004. But it has been in use since at least 1995. At least some writers compare it to the more familiar underclass:
Usage examples of "overclass".
Ashika, who kept it concealed from the overclass, the ones who ran and ruled the city.