Source : Webster's Revised Unabridged Dictionary (1913)

Exhalation \Ex`ha*la"tion\, n. [L. exhalatio: cf. F. exhalaison,
   exhalation.]
   1. The act or process of exhaling, or sending forth in the
      form of steam or vapor; evaporation.

   2. That which is exhaled, or which rises in the form of
      vapor, fume, or steam; effluvium; emanation; as,
      exhalations from the earth or flowers, decaying matter,
      etc.

            Ye mists and exhalations, that now rise From hill or
            steaming lake.                        --Milton.

   3. A bright phenomenon; a meteor.

            I shall fall Like a bright exhalation in the
            evening.                              --Shak.

Source : WordNet®

exhalation
     n 1: exhaled breath [syn: {halitus}]
     2: the act of expelling air from the lungs [syn: {expiration},
        {breathing out}]