# Wiktionaryβ

## EnglishEdit

Wikipedia has an article on:
Wikipedia

### EtymologyEdit

Quadratic in the phrase refers to the squaring on the terms.

### NounEdit

1. (mathematics) A type of average, calculated as the square root of the mean of the squares, ie. ${\displaystyle Q={\sqrt {x_{1}^{2}+x_{2}^{2}+...+x_{n}^{2} \over n}}}$ .