halo vs annulus

halo and annulus both are nouns.

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

As nouns, halo and annulus are synonyms defined as:

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

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