From WordNet (r) 2.0 (August 2003) [wn]:
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]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Poster \Post"er\, n.
1. A large bill or placard intended to be posted in public
places.
[1913 Webster]
2. One who posts bills; a billposter.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Poster \Post"er\, n.
1. One who posts, or travels expeditiously; a courier.
"Posters of the sea and land." --Shak.
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2. A post horse. "Posters at full gallop." --C. Lever.
[1913 Webster]