Myalgic Encephalomyelitis, also known as Chronic Fatigue Syndrome, is a debilitating illness that affects millions of people worldwide. This condition is characterized by extreme fatigue, joint and muscle pain, impaired memory and concentration, headaches, and sleep disturbances. While Myalgic Encephalomyelitis is the most commonly used term to describe this illness, there are a few other synonyms used in medical literature, including postviral syndrome, chronic fatigue immune dysfunction syndrome, systemic exertion intolerance disease, and more recently, ME/CFS. Although there is still much to learn about this condition, recognizing the various synonyms used to describe it can help raise awareness and understanding of this often-misunderstood illness.