What is Circulation ?
Circulation is (noun) 1. the act of circulating The circulation of the new price list to all departments will take several days. banknotes which are in circulation banknotes which have been issued and are in use 2. the movement of blood around the body Rub your hands together to get the circulation going. He has poor circulation. 3. the number of copies of a magazine or newspaper which are sold The new editor hopes to increase the circulation.
source: Easier English, Student Dictionary Upper Intermediate Level