Trading volume refers to the total number of shares or contracts that are bought and sold in a security over a specific period, typically within a day. It is an important indicator of market activity and can be used as a measure of interest in a particular stock or commodity. High trading volumes generally indicate strong investor interest and confidence while low volumes may suggest lack of interest or uncertainty about the security. Trading volume can also provide insight into price movements, as high volume buying or selling can drive prices up or down respectively. Overall, trading volume is an important metric used by analysts to assess market activity and investor sentiment towards a particular financial instrument.