late 14c., "poisonous substance," from Latin virus "poison, sap of plants, slimy liquid, a potent juice," from Proto-Italic *weis-o-(s-) "poison," which is probably from a PIE root *ueis-, perhaps originally meaning "to melt away, to flow," used of foul or malodorous fluids, but with specialization in some languages to "poisonous fluid" (source also of Sanskrit visam "venom, poison," visah "poisonous;" Avestan vish- "poison;" Latin viscum "sticky substance, birdlime;" Greek ios "poison," ixos "mistletoe, birdlime;" Old Church Slavonic višnja "cherry;" Old Irish fi "poison;" Welsh gwy "poison"). The meaning "agent that causes infectious disease" is recorded by 1728 (in reference to venereal disease); the modern scientific use dates to the 1880s. The computer sense is from 1972.

1650s, "a crown," from Latin corona "a crown, a garland," in ancient Rome especially "a crown or garland bestowed for distinguished military service," from suffixed form of PIE root *sker- (2) "to turn, bend."

With many extended senses in botany, anatomy, etc. The two "crown" constellations, Corona Borealis (according to fable, the crown of Ariadne) and Corona Australis, are both Ptolemaic. Astronomical sense of "luminous circle observed around the sun during total eclipses" is from 1809. As a brand of Cuban cigar, 1876. The brand of Mexican pale lager beer dates from 1925.

type of RNA virus affecting birds and mammals, in humans as a respiratory tract infection, by 1968, is so called for the spikes that protrude from its membranes and resemble the corona of the sun; see corona.  Covid as a contraction of coronavirus disease seems to have been coined for the outbreak that began in China in 2019 (COVID-19).

type of very small virus, 1965, from parvi- "small, little" + connecting element -o- + virus.

"a small crown," c. 1400, crownet, from Old French coronete, diminutive of corone "a crown," from Latin corona "crown" (see crown (n.)).

1935, from combining form of virus + -logy. Related: Virological.