Original: The title of Archduke ( feminine : Archduchess ) ( German : Erzherzog , feminine form : Erzherzogin ) denotes a noble rank above Duke and below King , used primarily by princes of the Houses of Habsburg and Habsburg-Lorraine .
Simplified: Archduke ( Erzherzog ) is a title distinct from Grand Duke ( Großherzog or Großfürst ) that is used in some other German royal houses and still in sovereign Luxemburg .