What is the English translation of the Portuguese term "estado de direito"?
That would be a regime where (1) most people -- especially government officials -- respect the laws, and most of those who don't get punished by the state, and (2) the laws are made and changed only according to procedures specified by the law.
It is not the same as "democracy", although in practice it is a requisite thereof. Its opposite includes regimes where those who make the laws do not have to follow them.