What do you mean using the "long" and "short"?

-- What do you mean using the "long" and "short"?
I mean the term purchase of currency and the second term means selling the currency.
When you buy, are buying the U.S. dollar and selling yen. The purchase of currency equivalent to the purchase of a greater volume of currency. The Aptajer buy a greater volume of currency while secures high value of the currency.
In currency trading short pair USD \ JPY tops the trader to sell U.S. dollars and buying yen, Japan. Sell the currency equivalent of selling the largest amount of currency. The dealer may sell the currency when they feel that Qubmtha will go down.