Gugelhopf refers to a kind of traditional cake, a ring cake available in Germany, Austriam Switzerland and other European countries in a form of a ring. It is baked in a special pan called Bundt Pan, Tube Pan or Bundt cake pan (Gugelhupfform in German).
Pictures below is a Gugelhopf baked by my mother-in-law for our traditional get together, a Kaffee und Kuchen (Coffee and Cake) for Easter Sunday