[1] : The Collaborative International Dictionary of English v.0.48

hydration \hydra"tion\, n. chem.
   the act of becoming, or state of being, a hydrate.
   1913 webster

   water of hydration chem., water chemically combined with
      some substance to form a hydrate; -- distinguished from
      water of crystallization.
      1913 webster
see also:
water of hydration water of crystallization 

[2] : WordNet (r) 2.0

hydration
     n : the process of combining with water; usually reversible

Hydration >> H Words
Hydration, definition of term: Hydration
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