A constitution is the fundamental law of the state, containing the principles upon which government is founded, regulating the divisions of powers and the manner in which it is to be exercised. But no definition of constitution can be regarded as exhaustive.
A Constitution is the aggregate of laws and customs that forms the scheme for the arrangement of power-relationship inside a political community—the State. The system of administration of a political community, the state is embodied in a document called the Constitution. No constitution can remain static—it requires modifications in consistence with the changing socio-economic and political ideas. So Woodrow Wilson ways: Living political constitutions must be Darwinian in structure and practice. Thus a constitution, instead of being static, is dynamic in nature.
Constitution is the autobiography of power relationship. The organizational character of an institution is ascertained from its constitution. The constitution is a legal document which provides the administrative system and the nature of a state. The constitution may not be codified in writing. The British constitution, for example, is not a written one. So it is not codified. Constitution evolves and develops in consistence with the social, economic and political ideas and environment of the land and time. That is why it is said that constitutions grow and are not made.