How Do You Sell Stocks Like Forex Pairs and Profit?

Hello and Happy New Year!
I have a very basic question about metatrader 4 and trading stocks.
I think I should probably tell you that I have very little experience in trading stocks. But I have been trading forex for a year or so. After looking at some charts I thought I'd give stock market a try too. So I looked at my MT4 and saw that I am able to sell / buy stocks just as forex pairs. This confused me. How can I possibly sell a stock without buying it in the first place and make profit? I know I can buy stocks and then sell after the price rises to make a profit. But MT4 has a "sell" option for equities just like for Forex.

http://i.imgur.com/PV1uUdu.png



Just out of curiosity I "sold" a stock when it was already falling and cloed it after the price fell further down, and made a profit. I am unable to understand the logic behind this. Eg. if you buy EUR/USD that means you are buying EUR. and when you sell EUR/USD you actually buy USD. But how can this be applied to selling a stock without buying it first and then end up with a profit?

http://i.imgur.com/MfnhRO0.png

I hope what I am trying to explain clear to you guys.

when you short sell a stock, ur broker will lend it to you. The stock will come from the brokerage's own inventory, from another one of the firm's customers, or from another brokerage firm. The shares are sold and the proceeds are credited to your account. Sooner or later, you must "close" the short by buying back the same number of shares which is called covering and returning them to your broker. If the price drops, you can buy back the stock at the lower price and make a profit on the difference. If the price of the stock rises, you have to buy it back at the higher price, and you lose money.

Alejandro

Thanks Alahandro. So it is called short covering. I tried goggling many search queries but failed to find the answer before you replied.
http://www.investopedia.com/terms/s/shortcovering.asp