equinoctial circle vs celestial equator

equinoctial circle and celestial equator both are nouns.

Word	Noun	Adjective	Verb	Adverb
equinoctial circle	Yes	No	No	No
celestial equator	Yes	No	No	No

As nouns, equinoctial circle and celestial equator are synonyms defined as:

equinoctial circle and celestial equator: the great circle on the celestial sphere midway between the celestial poles

Other synonyms of equinoctial circle include equinoctial, equinoctial line.

equinoctial circle (noun)	celestial equator (noun)
the great circle on the celestial sphere midway between the celestial poles	the great circle on the celestial sphere midway between the celestial poles