short interest

n.
The total number of stocks, securities, or commodity shares in an account or in the market generally that have been sold short and not yet repurchased. Also called short account, short position.

The total number of shares of a security that have been sold short by customers and securities firms.

Investopedia Says:
Short interest is typically expressed as a percentage. For example, 3% short interest means that 3% of the outstanding shares are held short.

Related Links:
Find out how this figure can be a real eye-opener on market sentiment of a given stock. Short Interest: What It Tells Us
Have you ever correctly predicted a stock's decline or wondered how to be profitable in a bear market? Find out how and the risks involved. Short Selling Tutorial
This sinister version of short selling tries to profit by generating fear in the market place. Find out how you can help prevent "short and distort". The Short And Distort - Stock Manipulation In A Bear Market

Total amount of shares of stock that have been sold short and have not yet been repurchased to close out Short Positions. The short interest figure for the New York Stock Exchange, which is published monthly in newspapers, indicates how many investors think stock prices are about to fall. The Exchange reports all issues in which there are at least 5,000 shares sold short, and in which the short interest position had changed by at least 2,000 shares in the preceding month. The higher the short interest, the more people are expecting a downturn. Such short interest also represents potential buying pressure, however, since all short sales must eventually be covered by the purchase of shares. For this reason, a high short interest position is viewed as a bullish sign by many sophisticated market watchers. See also Selling Short; Short Interest Theory.