Source : Webster's Revised Unabridged Dictionary (1913)

Driftwood \Drift"wood`\, n.
   1. Wood drifted or floated by water.

   2. Fig.: Whatever is drifting or floating as on water.

            The current of humanity, with its heavy proportion
            of very useless driftwood.            -- New Your
                                                  Times.

Source : WordNet®

driftwood
     n : wood that is floating or that has been washed ashore