# Doppler effect

> English word · Noun

## Definitions
1. The apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves.

## Etymology
From Christian Andreas Doppler, the scientist who first proposed this effect.

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