n : a compound (as Glauber's salt) formed by the union of water with some other substance , vb, hy*drat*ed hy*drat*ing vt : to cause to take up or combine with water or the elements of water vi : to become a hydrate . Similar sounding terms: dirty dried dry out hy·dride Published under license with Merriam-Webster, Incorporated. © 1997-2004.
vt : to cause to take up or combine with water or the elements of water 
