What are futures?

A future is a contract traded on a regulated commodity exchange; it specifies a future date of delivery or receipt of a certain amount of a specific product or its cash equivalent value at the end of the term of the contract. All futures are exchange-traded contracts and they're standardized in terms of delivery date, amount and contract terms.

Future contracts generally run in length from three months to six months but can go up to twenty-four months in some areas of trade. A futures contract, unlike an option, is a commitment to buy, sell or deliver the underlying product in the future, therefore it is possible to lose more than the initial deposit, unlike options where the risk is limited to the option premium paid.

Traders, banks and other financial institutions often use futures contracts to speculate on the direction of an underlying instrument (including indices).

Stock index futures and financial instruments are not "commodities". It is no longer correct to refer to the futures market as the commodities or commodities futures market unless you are specifically refering to things such as metals, oil, or agricultural products. Actually, the financial futures represent many of the highest volume futures contracts.

Stock Futures are financial contracts where the underlying asset is an individual stock. Stock Future contract is an agreement to buy or sell a specified quantity of underlying equity share for a future date at a price agreed upon between the buyer and seller. The contracts have standardized specifications like market lot, expiry day, and unit of price quotation, tick size and method of settlement.

source : stockmarketforum