The Collaborative International Dictionary of English v.0.48:

Hauberk \Hau"berk\ (h[add]"b[~e]rk), n. [OF. hauberc, halberc,
   F. haubert, OHG. halsberc; hals neck + bergan to protect, G.
   bergen; akin to AS. healsbeorg, Icel. h[=a]lsbj["o]rg. See
   Collar, and Bury, v. t.]
   A coat of mail; especially, the long coat of mail of the
   European Middle Ages, as contrasted with the habergeon, which
   is shorter and sometimes sleeveless. By old writers it is
   often used synonymously with habergeon. See Habergeon.
   [Written variously hauberg, hauberque, hawberk, etc.]
   --Chaucer.
   [1913 Webster]

         Helm, nor hawberk's twisted mail.        --Gray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hauberk
    n 1: a long (usually sleeveless) tunic of chain mail formerly
         worn as defensive armor [syn: hauberk, byrnie]