Source : Webster's Revised Unabridged Dictionary (1913)

Narcosis \Nar*co"sis\, n. [NL., fr. Gr. na`rkwsis. See
   {Narcotic}.] (Med.)
   Privation of sense or consciousness, due to a narcotic.

Source : WordNet®

narcosis
     n : unconsciousness induced by narcotics or anesthesia