sign·post /ˈsaɪnˌpost/
  招牌柱,廣告柱,路標
  Sign·post n. A post on which a sign hangs, or on which papers are placed to give public notice of anything.
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  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