1. n. a drug that has a calming effect and therefore relieves anxiety, agitation, or behavioral excitement by depressing the central nervous system. The degree of sedation depends on the agent, the size of the dose, the method of administration, and the condition of the patient. A drug that sedates in small doses may induce sleep in larger doses and may be used as a hypnotic; such drugs are commonly known as sedative–hypnotics. Benzodiazepines are commonly used as sedatives.

2. adj. producing sedation.