geometric mean

geometric mean
—n
	Compare arithmetic mean the average value of a set of n integers, terms, or quantities, expressed as the nth root of their product

geometric mean n.
The nth root, usually the positive nth root, of a product of n factors.

geometric mean   The positive nth root of the product of a set of n numbers. For example, the geometric mean of 2 × 3 × 6 × 8 is the 4th root of 288, or approximately 4.12.

geometric mean definition

mathematics
The Nth root of the product of N numbers.
If each number in a list of numbers was replaced with their geometric mean, then multiplying them all together would still give the same result. The geometric mean thus gives an average "factor" in a context where numbers are multiplied together, e.g. compound interest.
Wolfram (http://mathworld.wolfram.com/GeometricMean.html).
(2007-03-16)