1. Astronomy. a. A faintly colored luminous ring appearing to surround a celestial body visible through a haze or thin cloud, especially such a ring around the moon or sun, caused by diffraction of light from suspended matter in the intervening medium. Also called aureole. b. The luminous, irregular envelope of highly ionized gas outside the chromosphere of the sun.

2. Architecture. The projecting top part of a cornice.

3. A cigar with a long, tapering body and blunt ends.

4. Anatomy. The crownlike upper portion of a bodily part or structure, such as the top of the head.

5. Botany. A crown-shaped, funnel-shaped, or trumpet-shaped outgrowth or appendage of the perianth of certain flowers, such as the daffodil or the spider lily. Also called crown.

6. Electricity. A faint glow enveloping the high-field electrode in a corona discharge, often accompanied by streamers directed toward the low-field electrode.