Going 'short' indicates that an investor believes that prices will drop and therefore will profit if they can buy back their position at a lower price. Going 'long' would indicate the opposite and that an investor believes prices will rise and so buys that asset. Many individual investors do not have the ability to go short an actual bond. To do so would require locating an existing holder of that bond and then borrowing it from them in order to sell it in the market. The borrowing involved may include the use of leverage, and if the price of the...
http://www.investopedia.com/articles/investing/051915/how-short-us-bond-market.asp