From WordNet (r) 3.0 (2006) [wn]:
sundog
n 1: a bright spot on the parhelic circle; caused by diffraction
by ice crystals; "two or more parhelia are usually seen at
once" [syn: parhelion, mock sun, sundog]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
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.
[1913 Webster]
2. A fragmentary rainbow; a small rainbow near the horizon;
-- called also dog and weathergaw.
[Webster 1913 Suppl.]