A weighted average is more heavily influenced by some of the numbers it is calculated from than others....more on Weighted average
Generally refers to the arithmetic average obtained by adding the products of numbers 'weighted' by a predetermined value.
An average in which data from one or more years has a greater effect than other years. For example, a three-year average, weighted towards the most recent years, might be calculated as (2004/5 x 3 + 2003/4 x 2 + 2002/3 x 1) / 6.
An average of data points calculated after weighting each data point by its statistical precision or another measure of importance of the data point. 
A statistical quantity calculated by multiplying each value in a group by an assigned weight, summin