Both narcotics and opioids are painkillers. Some people use the terms interchangeably. But technically, some narcotics aren't opioids at all.
Doctors overwhelmingly agree that they should use plain language when speaking to patients. There is a lot of jargon in the healthcare world; some studies show that doctors use up to 70 terms their patients don't understand in a single visit!
Here's what you should know about the terms narcotic and opioid.
A narcotic is a painkiller. The term narcotic comes from the Greek word for stupor, and the original term referred to anything that could dull senses and therefore relieve pain.
These days, because the vast majority of pain medications are opioids, some people use the term “opioids” and narcotics” synonymously although technically narcotic is a more broad term that refers to any painkiller, opioid or nonopioid.
Plenty of non-opioid medications exist, including ibuprofen, acetaminophen, and aspirin. Some people find that these medications are enough to quell pain, while others may require narcotic medication.
If your doctor proposes treating your pain with a narcotic, it's best to ask for clarification. Ask your doctor about the risks and benefits of any treatment for pain.
Opioids are a type of narcotic painkiller that are derived from the poppy plant or synthesized in a lab. Natural versions (like opium or heroin) come from poppy plants, while lab-created versions (like Vicodin) are synthesized. 
Opioids are powerful, and they can be helpful for people in a great deal of acute pain. But they are also associated with significant problems, including overdose deaths and physical dependence. 
To some people, there is no difference between an opioid and a narcotic. Your doctor may use these terms interchangeably. However, technically opioids are a subclass of narcotics, as described above.
The Controlled Substances Act, enforced by the Drug Enforcement Administration, places substances into schedules. In general, the lower the number on the schedule, the more dangerous the substance is thought to be.
When officials determine drug schedules, they consider these aspects of the drug:
Opioids appear at almost every level within the schedule. Over-the-counter drugs with a limited amount of codeine are Schedule V drugs, while substances like heroin are Schedule I. Non-opioid narcotics are typically Schedule V drugs.