[ dop-ler ]


  1. Christian Johann, 1803–53, Austrian physicist: discovered the Doppler effect.


/ dŏplər /

  1. Austrian physicist and astronomer who in 1842 explained the effect, now named for him, of variations in the frequency of waves as a result of the relative motion of the wave source with respect to the observer.

Discover More

Example Sentences

Collins’ protocol calls for additional imaging with a 3D or 4D Doppler, which allows a physician to evaluate the nooks and crannies of the fetus and the cord.

Routine prenatal care already typically involves one or two ultrasounds using a two-dimensional Doppler—which shows a flat, two-dimensional image on a screen— to check on fetal growth and health between weeks 18 and 22 of pregnancy.

It was first implemented in the 2019 summer Atlantic League via the “TrackMan,” a system that measures the flight of a baseball using a 3D Doppler radar.

From Ozy

That is, it was triggering a sequence of tornado warnings, based on Doppler radar indications of a rotating region in the lower cloud, called a mesocyclone.

In physics, the Doppler effect describes how a noise like a coming train will always sound different when it approaches than when it recedes.

On each orbit, the planets pull the star slightly, which can be detected by the Doppler effect.

Also new this year, in the wake of Sandy, NOAA will receive real time Doppler radar data from its “Hurricane Hunter” planes.

The idea, initiated by Christian Doppler at Prague in 1842, was originally applied to sound.

The method of detecting binary stars by means of the spectroscope is an application of Doppler's principle.

The principle that the refrangibility of light is altered by end-on motion was enunciated by Christian Doppler of Prague in 1842.

Angle, strength and Doppler movement were computed to find course and distance.

Spectroscopic determinations of the velocities, through the Doppler-principle, are generally expressed in km.





Dopp kitDoppler effect