All languages use a term derived from two Latin words: corona and virus. The second part came from Latin vīrus “poisonous substance ” especially a liquid one. At the end of the 19th century, it was speculated the existence of something too small to be seen by microscope or to be filtered (using a Chamberland filter). This substance filtered but still infectious was denominated a contagium vivum fluidum (soluble living germ) by Martinus Beijerinck. The first micrographs of bacteriophage (bacteria eaters, in concrete, coliphages) were published by Helmut Ruska in Germany in 1940, right during WWII. Félix d’Hérelle was on his death bed when they showed him an electron micrograph of a bacteriophage that proved once for all the nature of bacteriophages and put all discussions on their “ferment nature” to a rest.
The first part, corona, was coined in 1967 by June Almeida and David Tyrrell because of the resemblance under the microscope between the virus spikes (peplomer) and the solar corona. It was a Spanish astronomer, José Joaquín de Ferrer, who used stellar corona for the first time in 1809 based on his own observations of the 1806 solar eclipse in New York.
The Latin word corona means crown or wreath, it is a borrowing from Greek κορώνη (korone) “garland, wreath”. In Ancient Greek olive wreaths, κότινοςm (kotinos), were chaplets worn as the price for victorious athletes of the Ancient Olympic Games, according to the myth it was Heracles’ idea. Laurel wreaths were given at the end of Pythian Games, sacred to Apollo, patron of sports, to honor Daphne. We still use the term “laureate” as a synonym of awarded. In Rome, corona graminea was the gift for a distinguished military service and corona sutilis was worn by Roman rulers, as Etruscan rulers did. Roman emperors also wore the solar crown, especially in association with the cult of Sol Invictus, influenced also by Alexander the Great, who identified himself with the solar god Helios and Mithras. This crown will become later the Christian aureola.
The circle represents the cyclical time in nature, which is why is widely used in Midsummer or pagan harvest festivals like Dozynki in Poland. It might also mean eternity, reinforced by the use of evergreen leaves, as we do with the funeral wreaths. In Christianity, Advent wreaths are used to observe the season before Christmas. God is perfect and eternal. On the other hand, the crown of thorns was meant to mock and torment at the same time.