Source : Webster's Revised Unabridged Dictionary (1913)

Perspiration \Per`spi*ra"tion\, n. [Cf. F. perspiration.]
   1. The act or process of perspiring.

   2. That which is excreted through the skin; sweat.

   Note: A man of average weight throws off through the skin
         during 24 hours about 18 ounces of water, 300 grains of
         solid matter, and 400 grains of carbonic acid gas.
         Ordinarily, this constant exhalation is not apparent,
         and the excretion is then termed insensible
         perspiration.

Source : WordNet®

perspiration
     n 1: salty fluid secreted by sweat glands; "sweat poured off his
          brow" [syn: {sweat}, {sudor}]
     2: the process of the sweat glands of the skin secreting a
        salty fluid; "perspiration is a homeostatic process" [syn:
         {sweating}, {diaphoresis}, {sudation}, {hidrosis}]