The Collaborative International Dictionary of English v.0.48:

Evaporation \E*vap`o*ra"tion\, n. [L. evaporatio: cf. F.
   ['e]vaporation.]
   1. The process by which any substance is converted from a
      liquid state into, and carried off in, vapor; as, the
      evaporation of water, of ether, of camphor.
      [1913 Webster]

   2. The transformation of a portion of a fluid into vapor, in
      order to obtain the fixed matter contained in it in a
      state of greater consistence.
      [1913 Webster]

   3. That which is evaporated; vapor.
      [1913 Webster]

   4. (Steam Engine) See Vaporization.
      [1913 Webster]

WordNet (r) 3.0 (2006):

evaporation
    n 1: the process of becoming a vapor [syn: vaporization,
         vaporisation, vapor, vapour, evaporation]
    2: the process of extracting moisture [syn: dehydration,
       desiccation, drying up, evaporation]