A: Average order value is the average size of a won order: the total value of your won orders (price × quantity on every order row) divided by the number of won orders. Only orders at 100% probability are counted.

To report on it, add the Average Order Value widget from the Widget gallery in the Report centre. By default it shows the average order value by month. You can also group it by, for example, company, user, product or campaign.

The Sales funnel widget also shows an Avg. order value for each user, based on the deals in the funnel. A won order is only included in the funnel if it was an opportunity (1-99% probability) before it was won. Orders created directly at 100% probability are not included. The Included opportunities setting on the widget decides which deals are counted: Any counts all of them, and Related to completed appointments counts only opportunities and orders created from a completed appointment or involving a contact who took part in one.