'Water of hydration' definitions:

Definition of 'water of hydration'

(from WordNet)
noun
The water present in hydrated compounds [syn: water of crystallization, water of crystallisation, water of hydration]

Definition of 'Water of hydration'

From: GCIDE
  • Hydration \Hy*dra"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]