noun, plural an·nu·li [an-yuh-lahy] /ˈæn yəˌlaɪ/, an·nu·lus·es.
Origin of annulus
Examples from the Web for annuli
This corresponds to the usual presence (in the Rhynchobdellidae) of three annuli to each segment.
As remarked, the prevalent number of annuli to a segment is three in the Rhynchobdellidae.
An eye-like spot in the Wings of many Lepidoptera, consisting of annuli of different colours, inclosing a central spot or pupil.An Introduction to Entomology: Vol. IV (of 4)|William Kirby
This phrase is somewhat obscure: "annuli ferrei sicut solebat fieri in cista Norensi."
But in that group (Cystobranchus) there may be as many as eight annuli.