Source : Webster's Revised Unabridged Dictionary (1913)

Luthern \Lu"thern\, n. [F. lucarne a dormer, dormer window,
   garret window, L. lucerna lamp, fr. lucere to be light or
   clear, fr. lux light. See {Light}, n., and cf. {Lucarne}.]
   (Arch.)
   A dormer window. See {Dormer}.