Source : Webster's Revised Unabridged Dictionary (1913)

Breather \Breath"er\, n.
   1. One who breathes. Hence:
      (a) One who lives.
      (b) One who utters.
      (c) One who animates or inspires.

   2. That which puts one out of breath, as violent exercise.
      [Colloq.]

Source : WordNet®

breather
     n 1: a short respite [syn: {breath}, {breathing place}, {breathing
          space}, {breathing spell}, {breathing time}]
     2: air passage provided by a retractable device containing
        intake and exhaust pipes; permits a submarine to stay
        submerged for extended periods of time [syn: {snorkel}, {schnorkel},
         {schnorchel}, {snorkel breather}]