A secular state is an idea pertaining to secularity, whereby a state is or purports to be officially neutral in matters of religion, supporting neither religion nor irreligion.

As a preliminary definition, secularism is an idealized vision of political life that "strains metaphysics out of politics" and "dredges out of public life as much cultural density and depth as possible" in order to secure the authority of public reason and a rational morality, and the legitimacy of both to govern within the territorial boundaries of the nation-state until such a time as they can govern universally.