Polity | constitution vs polity

Constitution    :  is a book..

•  A written document which is the rule of the land.
•  Constitution is a branch of legal studies,
• source of powers and functions on which system runs.
• constitute the legal basis of a polity, organisation or other type of entity.

Polity: polity is the constitution in run, I.e actual functioning of the constitution.

• studying of the constitution will be termed as polity.
•  Is a wider term and study of constitution is just a part of it..
• On the other hand is a study of administration and political science.
•  the actual running system or study of how the 
• system is running is polity.
• It will also include other things which are not mentioned in our constitution but are very much essential.