The Collaborative International Dictionary of English v.0.48:

Torsk \Torsk\, n. [Dan.; akin to Icel. [thorn]orskr a codfish,
   G. dorsch.] (Zool.)
   (a) The cusk. See Cusk.
   (b) The codfish. Called also tusk.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cusk \Cusk\ (k[u^]sk), n. (Zool.)
   A large, edible, marine fish (Brosmius brosme), allied to
   the cod, common on the northern coasts of Europe and America;
   -- called also tusk and torsk.
   [1913 Webster]

WordNet (r) 3.0 (2006):

torsk
    n 1: large edible marine fish of northern coastal waters;
         related to cod [syn: cusk, torsk, Brosme brosme]