noun.
A long sled without runners, with the front end curled upwards, which may be pulled across snow by a cord or used to coast down hills.
noun.
A similar sled of wood, pulled by dogs, possibly with steel runners, made to transport cargo.
noun.
a winter hat or ski mask
noun.
Something which, once it starts going (figuratively) downhill, is unstoppable until it reaches the bottom.
verb.
to slide down a hill on a toboggan or other object
verb.
to (figuratively) go downhill unstoppably until one reaches the bottom.