mock sun vs sundog

mock sun and sundog both are nouns.

Word	Noun	Adjective	Verb	Adverb
mock sun	Yes	No	No	No
sundog	Yes	No	No	No

As nouns, mock sun and sundog are synonyms defined as:

mock sun and sundog: a bright spot on the parhelic circle; caused by diffraction by ice crystals

Other synonyms of mock sun include parhelion.

mock sun (noun)	sundog (noun)
a bright spot on the parhelic circle; caused by diffraction by ice crystals	a bright spot on the parhelic circle; caused by diffraction by ice crystals