What is the definition of Shares Outstanding or Outstanding Shares?

Shares outstanding simply means the company's stock owned by shareholders, including share blocks held by institutional investors and restricted shares owned by the company's officers and insiders.  This is normally used to determine the price of the stocks when the value of the company is also available. 

How to calculate shares outstanding 

The number of stocks outstanding is equal to the number of issued shares minus the number of shares held in the company's treasury. It's also equal to the float (shares available to the public and excludes any restricted shares, or shares held by company officers or insiders) plus any restricted shares.