The term refers to the number of NFT transactions performed on different platforms over a specific time frame.
The Long Explanation
In web3, it refers to the number of NFT or crypto transactions carried out during a specific time period on different blockchain platforms.
When there is an increase in the trade volume, it indicates an increased interest in an NFT or crypto asset, as more of it will be traded. On the other hand, when the trade volume decreases, it is an indication of reduced interest in the NFT or crypto asset.
Each NFT transaction happens between a buyer and a seller. When an agreement is reached and an asset is sold, the transaction gets recorded by the platform that facilitates the trade. All the data recorded this ways are used to calculate the trade volume.