幻日

[ noun ]
a bright spot on the parhelic circle; caused by diffraction by ice crystals
<noun.phenomenon>
two or more parhelia are usually seen at once

Sundog \Sun"dog`\, n. (Meteorol.)
1. A luminous spot occasionally seen a few degrees from the
sun, supposed to be formed by the intersection of two or
more halos, or in a manner similar to that of halos.

2. A fragmentary rainbow; a small rainbow near the horizon;
-- called also {dog} and {weathergaw}.
[Webster 1913 Suppl.]