The amount of trading in an asset done over a set time period, often expressed in units (shares, contracts) but sometimes notional.
Use the volume tag when your question has to do with the trading activity in an asset over a time period, especially if you are measuring or trying to predict trading activity. Volume is often expressed in units (shares or contracts) but sometimes notional. Note that volume differs from the number of trades. For example, a stock might trade 8 times in a day; however, maybe 100 shares (at a price near USD 10) trades seven of those times and 1000 shares trades the other time (at a price near USD 11). In that case, the number of trades would be 8, the volume would be 1700 shares, and the notional traded would be USD 18,000.
