Doppler effect

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

Doppler effect (plural Doppler effects)

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.
   • 2016, Ian McEwan, Nutshell, Vintage, page 85:

     Along the street, a delivery van’s pop music approaches and recedes with a faint Doppler effect, the cheerless band lifting and dipping a microtone.

• Doppler shift

• blueshifted
• redshifted