plu·toc·ra·cy 
(pl-tŏkrə-sē)
(pl-tŏkrə-sē)n. pl. plu·toc·ra·cies
1. Government by the wealthy.
2. A wealthy class that controls a government.
3. A government or state in which the wealthy rule.
[Greek ploutokratiā : ploutos, wealth; see pleu- in the Appendix of Indo-European roots + -kratiā, -cracy.]
pluto·crat′ (pltə-krăt′) n.
plu′to·cratic, plu′to·crati·cal adj.
plu′to·crati·cal·ly adv.