Ma'anar ƙamus na kalmar "hydrate" ita ce ƙara ruwa ko danshi a cikin wani abu, ko zama ko kiyaye wani abu a cikin yanayin ruwa ko ruwa. Hakanan yana iya komawa zuwa wani fili wanda ya ƙunshi kwayoyin ruwa, kamar gishiri mai ruwa. Gabaɗaya, ruwa yana nufin tsarin ƙara ruwa ko wasu ruwaye don kiyaye matakan da suka dace a cikin jiki ko don hana bushewa.
