Source : Webster's Revised Unabridged Dictionary (1913)

Haiduck \Hai"duck\, n. [G. haiduck, heiduck, fr. Hung. hajdu.]
   Formerly, a mercenary foot soldier in Hungary, now, a
   halberdier of a Hungarian noble, or an attendant in German or
   Hungarian courts. [Written also {hayduck}, {heiduc},
   {heiduck}, and {heyduk}.]