myalgic encephalomeyelitis/chronic fatigue syndrome (MONDO_0005404, a Monarch Disease Ontology id) is a medical condition characterized by long-term fatigue and other symptoms that limit a person's ability to carry out ordinary daily activities. Also known as: CFS, Postviral fatigue syndrome, chronic fatigue immune dysfunction syndrome, chronic fatigue syndrome, myalgic encephalitis, myalgic encephalomyelitis, systemic exertion intolerance disease.