redshift /ˈɹɛdˌʃɪft/noun 1verb 1forms 3 noun1 •An increase in the wavelength of a photon or of light while in transit, corresponding to a lower frequency and a shift toward the red end of the electromagnetic spectrum. verb1 •(ergative) (said of light or a photon) To shift toward the red end of the electromagnetic spectrum while in transit; to change to a longer wavelength and a lower frequency. formsredshifted · redshifting · redshifts