early 15c., "alleviation of pain;" 1540s, "act of making calm," from Middle French sédation and directly from Latin sedationem (nominative sedatio) "a quieting, assuaging, a calming," noun of action from past participle stem of sedare (see sedate (adj.)).
sedation se·da·tion (sĭ-dā'shən)
Reduction of anxiety, stress, irritability, or excitement by administration of a sedative agent or drug.
The state or condition induced by a sedative.