The fundamental laws of a state. It may be either despotic,
aristocratic, democratic, or mixed.
To give a nation a constitution
is to give it fixed laws even to the limitation of the sovereign's
rights, so that the people are not under the arbitrary caprice of a
ruler, but under a known code of laws. A despotism or autocracy is
solely under the unrestricted will of the despot or autocrat.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894