The Collaborative International Dictionary of English v.0.48:

Toboggan \To*bog"gan\, n. [Corruption of American Indian
   odabagan a sled.]
   A kind of sledge made of pliable board, turned up at one or
   both ends, used for coasting down hills or prepared inclined
   planes; also, a sleigh or sledge, to be drawn by dogs, or by
   hand, over soft and deep snow. [Written also tobogan, and
   tarbogan.]
   [1913 Webster]