In statistics the term median is used to define or determine that which is the middle, statistically it is the midpoint (50th percentile) of a large set of numbers.
Accordingly this is the number you would use to find the middle of a series of numbers that are widely distributed (say: number of nodes, income in dollars, price of home, etc.).
It is not "average." Average is the mean.
example:
10, 9, 8, 1, 0, 0, 0, 0, 0, 0. (10 numbers, divided by 10 would give you a mean of 2.8.)
But the median of the same set of numbers is 0, since it is the middle number of that set of numbers.
The US Census Bureau has been using median in place of mean for its income statistics for years. The fact is that the current (1998) median household income for an American is $38,000. I think it is safe to safe to say that in the US most of the wealth is not redistributed.