hi.....
derivatives used in stock market.....
there are 2 type of trading in the market.....
first of all, u can buy or sell shares at normal price in the market rate, in which the market is goin on......
second, u just think where the market will be goin on in the future......
so u just buy the shares at ur rate i.e. price is putting by u... or sell shares at ur future rate not at the spot rate.......
this mkt is known as future market or option market......