parhelic circle vs parhelic ring

parhelic circle and parhelic ring both are nouns.

Word	Noun	Adjective	Verb	Adverb
parhelic circle	Yes	No	No	No
parhelic ring	Yes	No	No	No

As nouns, parhelic circle and parhelic ring are synonyms defined as:

parhelic circle and parhelic ring: a luminous halo parallel to the horizon at the altitude of the sun; caused by ice crystals in the atmosphere

Other synonyms of parhelic circle include solar halo.

parhelic circle (noun)	parhelic ring (noun)
a luminous halo parallel to the horizon at the altitude of the sun; caused by ice crystals in the atmosphere	a luminous halo parallel to the horizon at the altitude of the sun; caused by ice crystals in the atmosphere