solar halo vs parhelic circle

solar halo and parhelic circle both are nouns.

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

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

solar halo and parhelic circle: 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 ring.

solar halo (noun)	parhelic circle (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