The term "government by the best citizens" is often used to describe an aristocracy. An aristocracy is a form of government in which power is held by a small group of people who are considered to be the best or most noble citizens. This group may be made up of members of a certain social class, such as the nobility or wealthy elite, or it may be based on qualities such as education, experience, or expertise.
In contrast, a democracy is a form of government in which power is held by the people, either directly or through elected representatives. An oligarchy is a form of government in which power is held by a small group of people, often based on wealth or political influence. A plutocracy is a form of government in which power is held by the wealthy.