solar halo vs parhelic ring

solar halo and parhelic ring both are nouns.

Word	Noun	Adjective	Verb	Adverb
solar halo	Yes	No	No	No
parhelic ring	Yes	No	No	No

As nouns, solar halo and parhelic ring are synonyms defined as:

solar halo 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 solar halo include parhelic circle.

solar halo (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