In the context of options trading, the strike price is the price at which the option can be exercised. In other words, it is the predetermined price at which the underlying security or index can be bought or sold, depending on whether the option is a call option or a put option.

In the case of the Nifty 50 index, the strike price refers to the price at which the option on the Nifty 50 index can be exercised. For example, if a call option on the Nifty 50 index has a strike price of 10,000, this means that the option holder has the right to buy the Nifty 50 index at a price of 10,000 on or before the expiration date of the option. Similarly, if a put option on the Nifty 50 index has a strike price of 10,000, this means that the option holder has the right to sell the Nifty 50 index at a price of 10,000 on or before the expiration date of the option.
The strike price is an important factor in determining the value of an option. It determines the potential profit or loss for the option holder, as well as the likelihood of the option being exercised. Options with a lower strike price are generally considered to be less risky, while options with a higher strike price are considered to be riskier.

In the share market, the strike price is a key element in the pricing of options and plays a role in the overall supply and demand dynamics of the options market. It is important for investors and traders to understand the concept of strike price in order to make informed decisions about buying and selling options.