Source : Webster's Revised Unabridged Dictionary (1913)

Poster \Post"er\, n.
   1. A large bill or placard intended to be posted in public
      places.

   2. One who posts bills; a billposter.

Poster \Post"er\, n.
   1. One who posts, or travels expeditiously; a courier.
      ``Posters of the sea and land.'' --Shak.

   2. A post horse. ``Posters at full gallop.'' --C. Lever.

Source : WordNet®

poster
     n 1: a sign posted in a public place as an advertisement; "a
          poster advertised the coming attractions" [syn: {posting},
           {placard}, {notice}, {bill}, {card}]
     2: someone who pastes up bills or placards on walls or
        billboards [syn: {bill poster}, {bill sticker}]
     3: a horse kept at an inn or post house for use by mail
        carriers or for rent to travelers [syn: {post horse}]