noun
: a vapor lamp in which the fluorescence of cadmium vapor produces red light whose wavelength taken as 6438.4696 international angstroms is used as a standard of length
noun
: a vapor lamp in which the fluorescence of cadmium vapor produces red light whose wavelength taken as 6438.4696 international angstroms is used as a standard of length
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012