A short, as a noun, also known as a short seller, refers to a person who sells a contract or is prepared to buy the spot.
Short selling, as a verb, is the activity of selling a spot contract other than for hedging purposes.
In trading, due to the wrong direction of buying or selling, resulting in a loss on the book, in order not to expand the loss and stop the liquidation of positions, called cut.
Long, on, point to bought some kind of currency, thus much that kind of currency position, also called long.
A short squeeze is a situation in which prices are forced up by a lack of supply in the market.