The Collaborative International Dictionary of English v.0.48:

Streamer \Stream"er\, n.
   1. An ensign, flag, or pennant, which floats in the wind;
      specifically, a long, narrow, ribbonlike flag.
      [1913 Webster]

            Brave Rupert from afar appears,
            Whose waving streamers the glad general knows.
                                                  --Dryden.
      [1913 Webster]

   3. A stream or column of light shooting upward from the
      horizon, constituting one of the forms of the aurora
      borealis. --Macaulay.
      [1913 Webster]

            While overhead the North's dumb streamers shoot.
                                                  --Lowell.
      [1913 Webster]

   3. (Mining) A searcher for stream tin.
      [1913 Webster]

   4. (Journalism) a banner.
      [PJC]

WordNet (r) 3.0 (2006):

streamer
    n 1: light that streams; "streamers of flames"
    2: a newspaper headline that runs across the full page [syn:
       streamer, banner]
    3: a long flag; often tapering [syn: pennant, pennon,
       streamer, waft]
    4: long strip of cloth or paper used for decoration or
       advertising [syn: banner, streamer]