CoinucationVolume
Trading volume is the total amount of an asset bought and sold over a period, usually 24 hours, measured in units or dollars.
Volume measures how much trading activity an asset has. A 24-hour volume of 30 billion dollars for Bitcoin means that 30 billion dollars' worth of BTC changed hands across the exchanges being tracked in the last day. Volume is reported both in coin units and in dollar terms, and it is usually shown next to price and market cap on data sites.
High volume relative to market cap suggests an asset is actively traded and that large orders can be filled without moving the price much. Very low volume is a warning sign: a token with a 100 million dollar market cap but only 50,000 dollars of daily volume may be impossible to sell in size. Sudden spikes in volume often accompany major news or sharp price moves.
Reported volume is not always real. Some exchanges and tokens inflate volume through wash trading, where the same party buys and sells to itself. Reputable data providers try to filter this out, but comparing volume across several trustworthy exchanges is still worthwhile.