ar·is·toc·ra·cy 
(ăr′ĭ-stŏkrə-sē)
(ăr′ĭ-stŏkrə-sē)n. pl. ar·is·toc·ra·cies
1. A hereditary ruling class; nobility.
2.
a. Government by a ruling class.
b. A state or country having this form of government.
3.
a. Government by the citizens deemed to be best qualified to lead.
b. A state having such a government.
4. A group or class considered superior to others.
[Late Latin aristocratia, government by the best, from Greek aristokratiā : aristos, best; see ar- in the Appendix of Indo-European roots + -kratiā, -cracy.]