Select the most appropriate one-word substitution for the given group of words. 

A state, society, or group governed by old people.

Gerontocracy

The most appropriate one-word substitution for a state, society, or group governed by old people is gerontocracy.

• Neocracy means a government ruled by young people.
• Secular means not connected with religious or spiritual matters.
• Omnipresent means present everywhere at the same time.

The word gerontocracy is derived from the Greek words geron, meaning "old man", and kratos, meaning "rule". It is a form of government in which the elders or older members of society have the most power. In gerontocratic societies, the laws and policies of the government are typically made by a council of elders, and the younger members of society are often excluded from positions of power.