Source : Webster's Revised Unabridged Dictionary (1913)

Signpost \Sign"post`\, n.
   A post on which a sign hangs, or on which papers are placed
   to give public notice of anything.

Source : WordNet®

signpost
     n : a post bearing a sign that gives directions or shows the way
         [syn: {guidepost}]
     v : mark with a signpost, as of a path