LNG Chart, page-22

Actually no. They're stupid terms. Long is actually short for "buy long" and short is actually short for "short sell". See:

http://www.investopedia.com/university/shortselling/shortselling1.asp

In particular:
"When an investor goes long on an investment, it means that he or she has bought a stock believing its price will rise in the future. Conversely, when an investor goes short, he or she is anticipating a decrease in share price."