An Etymological Dictionary of the German Language/Durchlaucht

by Friedrich Kluge

Durchlaucht, ‘Serene Highness,’ simply ModHG. with MidG. vowel au; MidHG. and MidG. durchlûht, partic. for MidHG. durchliuhtet, ‘illustrious,’ from durhliuhten, ‘to shine, light through, illuminate.’ See Erlaucht, leuchten.