luffer
  變幅機構
  Lou·ver, Lou·vre  n.  Arch. A small lantern. See Lantern, 2 (a). [Written also lover, loover, lovery, and luffer.]
  Louver boards or Louver boarding, the sloping boards set to shed rainwater outward in openings which are to be left otherwise unfilled; as belfry windows, the openings of a louver, etc.
  Louver work, slatted work.
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  Luf·fer n.  Arch. See Louver.
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