Sedation :: Sedation (n.) The act of calming, or the state of being calm..
Sedative :: Sedative (a.) Tending to calm, moderate, or tranquilize.
Sedative :: Sedative (a.) allaying irritability and irritation; assuaging pain.
Sedative :: Sedative (n.) A remedy which allays irritability and irritation, and irritative activity or pain..