Ma'anar ƙamus na kalmar "hormone antidiuretic" (ADH) tana nufin wani hormone da hypothalamus ke samarwa da kuma fitar da glandan pituitary wanda ke daidaita yawan ruwa a cikin jiki ta hanyar sarrafa adadin fitsarin da kodan ke samarwa. ADH yana aiki ta hanyar ƙara sake dawowa da ruwa a cikin kodan, wanda ke rage yawan ruwan da ke ɓacewa a cikin fitsari kuma yana taimakawa wajen kiyaye ma'aunin ruwan jiki. An kuma san shi da vasopressin kuma yana taka muhimmiyar rawa wajen daidaita karfin jini da ma'aunin electrolyte.