annulus vs halo

annulus and halo both are nouns.

Word	Noun	Adjective	Verb	Adverb
annulus	Yes	No	No	No
halo	Yes	No	No	No

As nouns, annulus and halo are synonyms defined as:

Other synonyms of annulus include anchor ring, doughnut, ring.

annulus (noun)	halo (noun)
(Fungi) a remnant of the partial veil that in mature mushrooms surrounds the stem like a collar	an indication of radiant light drawn around the head of a saint
a toroidal shape	a circle of light around the sun or moon
	a toroidal shape