Mathematics To calculate the average of: average a set of numbers. To do or have an average of: averaged three hours of work a day. To distribute proportionately: average one's income over four years so as to minimize the tax rate.To be or amount to an average: Some sparrows are six inches long, but they average smaller. Our expenses averaged out to 45 dollars per day. average down To purchase shares of the same security at successively lower prices in order to reduce the average price of one's position.average up To purchase shares of the same security at successively higher prices in order to achieve a larger position at an average price that is lower than the current market value.