The term "Viking" is more of a description of people who were explorers from Scandinavia whose purpose for sailing was to raid and trade from other lands. They were considered very influential pirates who changed the cultural and historical landscape of Northern Europe from the late 700's through the mid 1100's C.E.
Since it isn't considered an "ethnic" term as much as a "vocational" term, Vikings came fro several countries that included Denmark, Sweden, and Norway.
Vikings were known for their superior weapons - swords with purified steel called crucible steel, as well as their superior ship building.
