Meaning refers to the difference between the spot price and the futures price of a specific commodity at a specific time and place, and the cost requirement is not too high.

Stock index discount means that the price of stock index futures is lower than the spot price. When it comes to discount in stock index futures, we usually say basis, because stock index discount refers to the change of basis, which means that the difference between the spot price and futures price of a particular commodity at a certain time and place should not be too high.