Source : Webster's Revised Unabridged Dictionary (1913)

Bulletin \Bul"le*tin\, n. [F. bulletin, fr. It. bullettino, dim.
   of bulletta, dim. of bulla, bolla, an edict of the pope, from
   L. bulla bubble. See {Bull} an edict.]
   1. A brief statement of facts respecting some passing event,
      as military operations or the health of some distinguished
      personage, issued by authority for the information of the
      public.

   2. Any public notice or announcement, especially of news
      recently received.

   3. A periodical publication, especially one containing the
      proceeding of a society.

   {Bulletin board}, a board on which announcements are put,
      particularly at newsrooms, newspaper offices, etc.

Source : WordNet®

bulletin board
     n 1: a computer that is running software that allows users to
          leave messages and access information of general
          interest [syn: {bulletin board system}, {electronic
          bulletin board}, {bbs}]
     2: a board that hangs on a wall; displays announcements [syn: {notice
        board}]

Source : Free On-Line Dictionary of Computing

bulletin board
     
        {bulletin board system}