lightness, light - the visual effect of illumination on objects or scenes as created in pictures; "he could paint the lightest light and the darkest dark"

fairy circle, fairy ring - a ring of fungi marking the periphery of the perennial underground growth of the mycelium

toroid - the doughnut-shaped object enclosed by a torus

atmospheric phenomenon - a physical phenomenon associated with the atmosphere

parhelic circle, parhelic ring, solar halo - a luminous halo parallel to the horizon at the altitude of the sun; caused by ice crystals in the atmosphere