Any feature that manifests a disease condition is a symptom, and it can be either physical or mental.
Symptoms help us to find out or identify the disease condition or an underlying illness. Symptoms show us abnormal medical conditions and give us evidence of our sickness. We have a set of symptoms when we suffer from a common cold or flu. Similarly, there are other causes and symptoms of heart attack or stroke, common causes and symptoms of epilepsy, and more. Chronic symptoms remain with us for a long time, and the ones that return after being treated are called relapsing symptoms.
When a set of symptoms occur together, then it is a disease. Symptoms are essential for the diagnosis and to find out more about the causes and treatment. The patient is the first to experience and describe the symptoms to the doctor who can base his diagnosis and begin treatment.