Doppler effect
Doppler effect
nounDefinition of DOPPLER EFFECT
: a change in the frequency with which waves (as sound, light, or radio waves) from a given source reach an observer when the source and the observer are in motion with respect to each other so that the frequency increases or decreases according to the speed at which the distance is decreasing or increasing—compare shift a
Learn More About
Seen & Heard 
What made you want to look up Doppler effect? Please tell us where you read or heard it (including the quote, if possible).
