annulus vs anchor ring

annulus and anchor ring both are nouns.

Word	Noun	Adjective	Verb	Adverb
annulus	Yes	No	No	No
anchor ring	Yes	No	No	No

As nouns, annulus and anchor ring are synonyms defined as:

Other synonyms of annulus include doughnut, halo, ring.

annulus (noun)	anchor ring (noun)
(Fungi) a remnant of the partial veil that in mature mushrooms surrounds the stem like a collar	a toroidal shape
a toroidal shape