Harmonic mean

# Harmonic mean

WordNet

### noun

(1)   The mean of n numbers expressed as the reciprocal of the arithmetic mean of the reciprocals of the numbers
Wiktonary

### Noun

1. A type of measure of central tendency calculated as the reciprocal of the mean of the reciprocals, ie, $H = \left\{ n \over \left\{1 \over x_1\right\} + \left\{1 \over x_2\right\} + \cdots \left\{1 \over x_n\right\} \right\}$