noun (plural coronae /-nē, -nī/)
1 Astronomy The rarefied gaseous envelope of the sun and other stars. The sun’s corona is normally visible only during a total solar eclipse when it is seen as an irregularly shaped pearly glow surrounding the darkened disk of the moon.
- With the face of the Sun blocked by the Moon during a solar eclipse, the corona shines with the brightness of a full Moon.
- As the brilliant Sun is covered by the Moon, the pearly corona flashes into view, the sky darkens, and all of nature seems to come to a halt.
- Like the chromosphere, the corona can only be seen by eye during a total eclipse, although there are other technical ways to observe it between times.
1.1 (also corona discharge) Physics The glow around a conductor at high potential.
- In this process, the difficult-to-bond plastic is exposed to a corona discharge, usually in the presence of air and at atmospheric pressure.
- The ion mobility cell is doped with ions produced by a corona discharge ionisation source.
- Instead of generating a lightning strike, the corona discharge, as it's called, flees objects such the masts of ships, power poles, antennas, and the wings of aircraft, causing the glow.
1.2A small circle of light seen around the sun or moon, due to diffraction by water droplets.
- Another effect that is caused by the interaction of the sun and water droplets, is the corona.
- But the corona owes its origin to diffraction rather than refraction.
- A circle around the sun or moon that is smaller than a halo with a 22-degree radius, is probably a corona.
2 Anatomy A crown or crownlike structure.
- The heart muscle has its own blood supply coming from a crown or corona of blood vessels that circle the heart, sending down branches to various parts of the muscle.
- In most species, the head carries a corona of cilia that draws a vortex of water into the mouth, which the rotifer sifts for food.
2.1 Botany The cup-shaped or trumpet-shaped outgrowth at the center of a daffodil or narcissus flower.
- In the flowers, corolla, corona and anther structure are similar, but the shape of the pollen tetrads in the two genera is different.
- The style projects from the corona of anthers and elongates with age.
- Contrast in spectral reflectance between the corona and corolla was evident only in Pachycarpus natalensis and Asclepias cucullata.
A long, straight-sided cigar.
- Eventually all the beautiful people were puffing robustos and coronas while schmoozing, partying and sauntering among the paparazzi.
- For instance, a corona that is typically 5.5 x 42 means that the cigar measures 5.5 inches in length and 42/60ths of an inch in diameter.
- I dropped the corona and it caught on the curtain.
late 19th century: from Spanish La Corona, literally 'the crown', originally a proprietary name.