Correct spelling for the English word "Luthern" is [lˈuːðən], [lˈuːðən], [l_ˈuː_ð_ə_n] (IPA phonetic alphabet).
A dormer or garret window.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.