Norovirus is a highly contagious viral infection that causes gastroenteritis. There are several synonyms for this infection, including the Norwalk virus, winter vomiting bug, stomach flu, and acute viral gastroenteritis. The Norwalk virus was first identified in 1972 in an outbreak of vomiting and diarrhea among schoolchildren in Norwalk, Ohio. Norovirus is commonly referred to as the stomach flu, although it is not related to influenza. Another synonym for norovirus, the winter vomiting bug, is due to the fact that outbreaks of norovirus are more common during the winter months. Overall, these synonyms are interchangeable and refer to the same viral infection.