A narcotic is literally a drug that induces sleep. The word "narcotic" is taken from the Greek word narkos, meaning "sleep." Narcotics can be either naturally grown or man-made. The term most commonly refers to such as heroin, morphine, and codeine.
The term narcotic can also be used to describe any illegal drug, including marijuana or cocaine, even though these drugs are not considered narcotics in the medical context. Due to this common confusion of the term, medical professionals typically refer to pharmacuetical narcotic pain relievers as "opioids" or "opioid analgesics."