Opioid: 1. A synthetic narcotic that resembles the naturally occurring opiates. 2. Any substance that binds to or otherwise affects the opiate receptors on the surface of the cell. From Healthy Resources 10 Rheumatoid Arthritis SymptomsWhat Is Exocrine Pancreatic Insufficiency?Understanding COVID-19 Testing and Treatment Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew Health Solutions From Our Sponsors