Greek aristokratia combines the idea of the best with an ending built on power. English received French and Late Latin forms.
Kratos is the deeper source of the compound ending -kratia.
Sources
- Merriam-Webster: aristocracy
The compound contains aristos and -kratia; French and Late Latin contributed.
- Merriam-Webster: -cracy
Greek kratos is the deeper source of the governmental ending.
- Online Etymology Dictionary: -cracy
Also built on *-cracy* (Greek -kratia, from kratos): democracy, autocracy, bureaucracy