blueshift /ˈbluːˌʃɪft/noun 1verb 1forms 3 noun1 •A decrease in the wavelength of a photon or of light while in transit, corresponding to a higher frequency and a shift toward the blue end of the electromagnetic spectrum. verb1 •(ergative) (said of light or a photon) To shift toward the blue end of the electromagnetic spectrum while in transit; to change to a shorter wavelength and a higher frequency. formsblueshifted · blueshifting · blueshifts