# Reynolds operator

> English word · Noun

## Definitions
1. A mathematical operator given by averaging something over a group action, satisfying a set of properties called Reynolds rules, and having applications in fluid dynamics and invariant theory.

## Etymology
They were introduced into fluid dynamics by Osbourne Reynolds (1895) and named by J. Kampé de Fériet (1934, 1935, 1949).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/reynolds-operator