aristocracy

Aristocracy came into English via Middle French aristocratie and Medieval Latin aristocratia, from Ancient Greek aristokratíā. That Greek word joined áristos, meaning 'best, noblest,' with -kratíā, from krátos, 'power, rule.'

The Greek term literally meant 'the rule of the best,' which in practice came to mean 'the best-born' — rule by nobility rather than by merit alone.

It shares its second half with other -cracy words, all built on Greek krátos, meaning power or rule.