annulus

[ an-yuh-luh s ]
/ ˈæn yə ləs /

noun, plural an·nu·li [an-yuh-lahy] /ˈæn yəˌlaɪ/, an·nu·lus·es.

a ring; a ringlike part, band, or space.
Geometry. the space between two concentric circles on a plane.
the veil remnant on a mushroom stalk.
a growth ring, as on the cross section of a tree trunk, that can be used to estimate age.

Origin of annulus

1555–65; < Latin, variant of ānulus, equivalent to ān(us) ring + -ulus -ule

Words nearby annulus

annulet, annulment, annuloplasty, annulorrhaphy, annulose, annulus, annulus hemorrhoidalis, annulus urethralis, annunciate, annunciation, annunciation lily

Example sentences from the Web for annulus

British Dictionary definitions for annulus

annulus
/ (ˈænjʊləs) /

noun plural -li (-ˌlaɪ) or -luses

the area between two concentric circles
a ring-shaped part, figure, or space

Word Origin for annulus

C16: from Latin, variant of ānulus ring

Medical definitions for annulus

annulus

n. pl. an•nu•lus•es

A circular or ring-shaped structure.

Scientific definitions for annulus

annulus
[ ăn′yə-ləs ]

Plural annuluses annuli (ăn′yə-lī′)

A ringlike figure, part, structure, or marking, such as a growth ring on the scale of a fish.
A ring or group of specialized cells around the sporangia of many ferns. By changing shape in response to variations in humidity, it breaks open the sporangium and then releases the spores with a whipping motion.
The ringlike remains of a membrane (called a veil), found around the stipes of certain basidiomycete mushrooms. The presence or absence of an annulus is often used to identify the species of an individual mushroom.
The figure bounded by and containing the area between two concentric circles.