Opiates are substances made from several species of the opium poppy plant that help relieve pain. These plants have been cultivated and used by humans for medicinal and recreational purposes over thousands of years. Morphine and heroin are well-known examples of opiates. 

Fully synthetic opioids are man-made substances created in laboratories that can also relieve pain. However, "opioid" is an umbrella category that can be used to include plant-derived opiates, semi-synthetic opioids such as oxycodone which have compounds from plant sources, and those that are made in laboratories.