hy·drate / ˈhīˌdrāt/ • n. Chem. a compound, typically a crystalline one, in which water molecules are chemically bound to another compound or an element.• v. [tr.] cause to absorb water. ∎ Chem. combine chemically with water molecules: [as adj.] (hydrated) hydrated silicate crystals. DERIVATIVES: hy·drat·a·ble adj.hy·dra·tion / hīˈdrāshən/ n.hy·dra·tor / -tər/ n.

hydrate (chem.) compound of water with another compound or an element. XIX. — F., f. Gr. húdōr, hudr- WATER; see -ATE2.
So hydride †hydrate; compound of hydrogen with an element or radical. XIX.

hydrate (hy-drayt)
1. vb. to undergo treatment or impregnation with water.
—hydration n.
2. n. a chemical compound in which one or more molecules of water are combined with a molecule of another substance.