"A troll is a supernatural being in Norse mythology and Scandinavian folklore. In origin, one of the meanings of the term troll was a negative synonym for a jötunn (plural jötnar), a being in Norse mythology, although the word was also used about witches, berserkers and various other evil magical figures."
Not until later, after the viking period according to Pete Nash, did the trolls we know and love become a separate race of creatures.
That depends on how you want to run your game.