Main Entry:

an·nu·lus

Pronunciation:

\ˈan-yə-ləs\

Function:

noun

Inflected Form(s):

plural an·nu·li \-ˌlī, -(ˌ)lē\ also an·nu·lus·es

Etymology:

Medieval Latin, from Latin anulus finger ring, from anus ring — more at anus

Date:

1563

1: ring2: a part, structure, or marking resembling a ring: as a: a line of cells around a fern sporangium that ruptures the sporangium by contracting b: a growth ring (as on the scale of a fish) that is used in estimating age