Coronaviruses — so-called because in electron micrographs the spikes projecting from the virus resemble a crown — are a group of viruses which have been isolated from people with common colds and have also been shown to produce common colds under experimental conditions. Their precise significance in the causation of the common cold is still undetermined.
One of a group of viruses, morphologically similar, ether-sensitive, and containing RNA that are responsible for some common colds and severe adult respiratory syndrome (SARS). They are so named because their microscopic appearance is that of a virus particle surrounded by a crown.
A group of viruses belonging to a genus that is responsible for causing respiratory illnesses and gastrointestinal infections is known as norovirus. These viruses can result in a range of symptoms, including respiratory disease and gastroenteritis.