Outstanding Shares

What Does Outstanding Shares Mean?
Stock currently held by investors, including restricted shares owned by the company's officers and insiders, as well as those held by the public. Shares that have been repurchased by the company are not considered outstanding stock. 

Also referred to as "issued and outstanding" if all repurchased shares have been retired.

Investopedia explains Outstanding Shares
This number is shown on a company's balance sheet under the heading "Capital Stock" and is more important than the authorized shares or float. It is used to calculate many metrics, including market capitalization and earnings per share (EPS).