Volume refers to the total number of future contracts that have been executed on the stock exchange on any given trading day
Let’s look at the same example which was discussed in the Future Open Interest section. Initially open interest was 1, as the only contract was between Sita and Noor. The next day 12 new contracts were opened between 12 different sellers and buyers, and the total open interest increased to 13. On this day the volume was 12, as 12 contracts got executed, however open interest was 13 as these are the number of open contracts.
Next day one more contract got opened between a new buyer and seller. Thus the open interest became 14, but the volume for that day was just 1 as only one contract got executed. The purchase by the buyer and sale by the seller of one futures contract equals a volume of 1.
For example if you see that the Volume for the near month Reliance future contract on the screener as 120,000, it means these many contracts were executed on the previous trading day.