What does it mean to be long on a stock?
In finance, a long position in a financial instrument means the holder of the position owns a positive amount of the instrument. The holder of the position has the expectation that the financial instrument will increase in value. This is known as a bullish position
This term does not have a definitive origin story. Some believe that to buy long or have a long position evolved naturally after short positions were described. Since long is the opposite of short it is a logical name for the opposite of short selling or shorting a stock.
The terms sell short and short position seem to have arisen in US stock and commodity markets sometime in about 1850.
In online forums long is used as a term to mean that you believe the price will go up over time and that you actually own the stock. For the sake of simplicity, long generally is betting that the price will go up.
“I am long on xyz, its outlook looks good and is eventually going to the moon!”
“What does long mean?”