A stock and a share are one and the same. They both represent a part of the capital of a joint stock company. In India it was always called shares whereas in the US they have been referred to as stocks.

Price of the stock is normally determined by profitability & growth prospects of the company. Normally, based on the attractiveness of the stock a P/E ratio is assigned by the market. Stock prices also depend on demand and supply as well as news flows.

You can place market orders or limit orders. In a limit order you define a price and the order will only be executed at a price better than that.A market order allows you to buy or sell a stock at the best available price.

Short selling is when you sell the shares without having delivery in your demat account. If you have short sold shares, then you can cover it back the same day. But if it’s not covered, you need to give delivery. If you are unable to give delivery, then the stock goes into auction and the losses via bidding get debited to your account.

Futures are derivative contracts created on an underlying asset at a specific price on a specified future date. Both the buyer and seller have to honour the contract on expiration. On the other hand, options give the buyer the right, but not the obligation, to buy or sell a certain underlying at a specific price on a specified date in future. The buyer can choose whether or not they want to exercise the right. The seller has an obligation to honor the contract. This is the primary difference between the two derivatives.

Additionally, futures require a higher margin requirement than options. The risks of trading in futures is also higher than options because of the unlimited losses they are exposed to.

Option price is depended upon strike price, time to expiration, interest rate, & volatility.

An American Options contract can be exercised on or before the expiration date. European Options can be exercised only on the expiration date. In India, we have European options.