SARS stands for "Severe Acute Respiratory Syndrome." It is a viral respiratory illness caused by a coronavirus, characterized by severe and sudden onset of respiratory symptoms. The term breaks down as follows: Severe indicates a serious condition, Acute refers to the sudden appearance of symptoms, Respiratory relates to the lungs being the primary affected organ, and Syndrome denotes a collection of symptoms occurring together. SARS was first identified in the early 2000s and caused a global outbreak before being contained.