hīˈdrāshən noun
( -s )
Etymology: hydrate (II) + -ion
1. : the act or process of combining with water: as
a. : the introduction of additional fluid into the body
hydration sometimes helps to reduce the concentration of toxic substances in the tissues
b. : a chemical reaction in which water takes part with the formation of only one product
hydration of ethylene to ethyl alcohol
especially : a reaction in which water takes part in the form of intact molecules
hydration of sodium sulfate to the decahydrate
— compare hydrolysis , solvation
c. : the addition of water to a calcium aluminate powder to produce cement
2. : the quality or state of being hydrated: as
a. : the condition of having adequate fluid in the body tissues
b. : a physical change in paper fibers due to adsorption and imbibition of water caused by prolonged beating