a usu coloured circle of usu diffracted light seen round and close to a luminous celestial body, e.g. the sun or moon
the tenuous outermost part of the atmosphere of the sun and other stars appearing as a halo round the moon's black disc during a total eclipse of the sun
the upper portion of a bodily part, e.g. a tooth or the skull
in botany, a circular appendage on the inner side of the corolla in the daffodil, jonquil, and similar flowers
a circular chandelier, esp in a church
the concave moulding on the upper part of the cornice on a classical building
[Latin corona: see crown1]