What is oligarchy do you think a lot of countries use this type of government

An oligarchy is a system of government run by a group of people versus other countries which are run by a single person. Usually they are wealthy or have political, military, or religious ties to justify their ruling. They pass down power to their relatives, and usually come from a long line of oligarchs. This is an authoritarian government. And it depends on the second question. Is it referring to how most governments today are run by political parties versus one individual and each term of that individual is merely just a different interpretation of that party's ideals? Or do you mean if they are actually identified as so, then no because only one or two oligarchs exist I think, present day because most are run by a single leader (regardless if democratic or authoritarian).