The Collaborative International Dictionary of English v.0.48:

Viking \Vi"king\, n. [Icel. v[imac]kingr, fr. v[imac]k a bay,
   inlet.]
   One belonging to the pirate crews from among the Northmen,
   who plundered the coasts of Europe in the eighth, ninth, and
   tenth centuries.
   [1913 Webster]

         Of grim Vikings, and the rapture
         Of the sea fight, and the capture,
         And the life of slavery.                 --Longfellow.
   [1913 Webster]

   Note: Viking differs in meaning from sea king, with which it
         is frequently confounded. "The sea king was a man
         connected with a royal race, either of the small kings
         of the country, or of the Haarfager family, and who, by
         right, received the title of king as soon he took the
         command of men, although only of a single ship's crew,
         and without having any land or kingdom . . . Vikings
         were merely pirates, alternately peasants and pirates,
         deriving the name of viking from the vicks, wicks, or
         inlets, on the coast in which they harbored with their
         long ships or rowing galleys." --Laing.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Viking
    n 1: any of the Scandinavian people who raided the coasts of
         Europe from the 8th to the 11th centuries

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "viking":
   AB, Ancient Mariner, Argonaut, Blackbeard, Captain Hook,
   Captain Kidd, Dylan, Flying Dutchman, Henry Morgan, Jean Lafitte,
   Neptune, OD, Poseidon, Varuna, able seaman, able-bodied seaman,
   air pirate, airplane hijacker, bluejacket, buccaneer, corsair,
   deep-sea man, fair-weather sailor, fisherman, hearty, jack,
   jack afloat, jack-tar, jacky, limey, lobsterman, mariner, matelot,
   navigator, picaroon, pirate, privateer, rover, sailor, salt,
   sea dog, sea king, sea rover, seafarer, seafaring man, seaman,
   shipman, skyjacker, tar, water dog, whaler, windjammer,
   windsailor



U.S. Gazetteer Places (2000):

Viking, MN -- U.S. city in Minnesota
   Population (2000):    92
   Housing Units (2000): 44
   Land area (2000):     0.510252 sq. miles (1.321546 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.510252 sq. miles (1.321546 sq. km)
   FIPS code:            67090
   Located within:       Minnesota (MN), FIPS 27
   Location:             48.219999 N, 96.406736 W
   ZIP Codes (1990):     56760
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Viking, MN
    Viking