Rule by the old people is known as

The term that refers to rule by old people is "gerontocracy." Gerontocracy comes from the Greek words "geron," meaning "old man," and "kratia," meaning "rule or power." In a gerontocracy, the people who hold power and make decisions are typically older individuals who are respected for their age and wisdom. This form of governance is based on the belief that older people have more experience, knowledge, and wisdom than younger generations and, therefore, should lead the society. Gerontocracy has been practiced in some societies throughout history, but it is not very common in modern times.