Difference between Parhelion and Sundog

What is the difference between Parhelion and Sundog?

Parhelion as a noun is a bright spot in the sky due to the refraction of the sun's image by ice crystals. while Sundog as a noun is either of two bright spots, caused by the refraction of sunlight through ice crystals, sometimes seen on the parhelic circle.

We hope you now know whether to use Parhelion or Sundog in your sentence.