CORONA

(astron.), luminous envelope round the sun outside the chromosphere, only observable during total solar eclipses; C. borealis and australis, constellations in N. and S. hemispheres; (meteor.) halo round the moon or sun due to diffraction by particles of moisture or dust; (arch.) projecting part of cornice, protecting the wall from weather; (bot.) appendages on inner side of corolla of flowers like daffodils and jonquils.