Londonrocks

Long = bought
Put = sold

So a short-call position would mean you have sold a call option to someone else. Say you're short a 50-strike call with a premium of $3.50. That means that at expiration, the long call holder (person you sold to) has the right to buy the stock at 50 and you have an obligation to sell at 50. Say that at expiration, the stock is 100. You need to buy the stock at 100 and sell it to the call holder for 50, so you lose 50 on the position, but get to keep the $3.50 premium.

For short option positions, it sometimes helps to remember that the max profit for an option-writer happens when it expires out of the money, and the max profit for the option-writer is the option premium.