The basic law or laws of a nation or a state which sets out how that state will be organized by deciding the powers and authorities of government between different political units, and by stating the basic law-making and structural principles of society.
The primary contract or law by which the government of a nation or state is set out and organized.
The constitution is colloquially referred to as the “#1 law of the land”; to which all of government, citizens, corporate persons and other laws must defer in the event of any conflict.
The Canadian Constitution is typical in stating that:
“The Constitution of Canada is the supreme law of Canada, and any law that is inconsistent with the provisions of the Constitution is, to the extent of the inconsistency, of no force or effect.”
Constitutions are not necessarily written and may be based on aged customs and conventions, as is the case, in part, in England and New Zealand (the USA, Canada and Australia all have written constitutions).