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1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Respirator \Res"pi*ra`tor\ (r?s"p?*r?`t?r), n. [Cf. F.
      respirateur.]
      A divice of gauze or wire, covering the mouth or nose, to
      prevent the inhalation of noxious substances, as dust or
      smoke. Being warmed by the breath, it tempers cold air
      passing through it, and may also be used for the inhalation
      of medicated vapors.
      [1913 Webster]