water of hydration

noun

Chemistry.

1. the portion of a hydrate that is represented as, or can be expelled as, water: now usually regarded as being in true molecular combination with the other atoms of the compound, and not existing in the compound as water.

water of hydration

1. Water that is chemically combined with other molecules to form a hydrate mineral and that is easily removed through heating.

Word History and Origins

Origin of water of hydration¹

First recorded in 1885–90