What is the meaning of Protectorate?

Government by a protector; especially, the government of England, Scotland, and Ireland by Oliver Cromwell.

The authority assumed by a superior power over an inferior or a dependent one, whereby the former protects the latter from invasion and shares in the management of its affairs but the protected state retains its nominal sovereignty.

An autonomous territory that is protected diplomatically or militarily against third parties by a stronger state or entity.