halo

A circular band of coloured light, visible around the sun or moon etc., caused by reflection and refraction of light by ice crystals in the atmosphere.

A cloud of gas and other matter surrounding and captured by the gravitational field of a large diffuse astronomical object, such as a galaxy or cluster of galaxies.

Anything resembling this band, such as an effect caused by imperfect developing of photographs.

Nimbus, a luminous disc, often of gold, around or over the heads of saints, etc., in religious paintings.

The metaphorical aura of glory, veneration or sentiment which surrounds an idealized entity.

(iconography) a circular annulus ring, frequently luminous, often golden, floating above the head

A circular brace used to keep the head and neck in position.

A rollbar placed in front of the driver, used to protect the cockpit of a open cockpit racecar.