annulus noun. ['anjʊlǝs] Pl. -li [-lʌɪ, -li:]. M16.
[Latin, late form of anulus dim. of anus ring (see ANUS).]
Chiefly Math. & Botany. A ring, a circle that is not filled in; spec. a partial veil forming a collar round the stalk in some agarics; the ring of thickened cells surrounding the sporangium of a fern.

[TahlilGaran] English Dictionary ▲