annulus

[ an-yuh-luhs ]

/ ˈæn yə ləs /

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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.

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Origin of annulus

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

Words nearby annulus

annulate, annulation, annulet, annulment, annulose, annulus, annunciate, annunciation, annunciator, annus horribilis, annus mirabilis

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use annulus in a sentence

Stonecutters Bridge in Hong Kong, which opened in December 2009, featured giant towers composed of 32 stainless-steel segments wrapped around a concrete annulus.
Five bridges that show how technology is changing|Jon Allsop|April 28, 2021|MIT Technology Review
That meant the region in which the center would balance was a ring, or annulus.
Can You Cut The Square … Into More Squares?|Zach Wissner-Gross|January 8, 2021|FiveThirtyEight
Thus a hot hoosh is preparing in the central vessel side by side with the melting of snow for cocoa or tea in the annulus.
The Home of the Blizzard|Douglas Mawson
Mettenius had laid stress upon various characters, but especially on the oblique annulus as distinctive.
Makers of British Botany; a collection of biographies by living botanists|Various

A distinctive feature is the incomplete annulus of the sporangium.
How to Know the Ferns|S. Leonard Bastin
The sporangia have very short stalks, and are not provided with an annulus at all.
How to Know the Ferns|S. Leonard Bastin
The rocky annulus which surrounds it is very lofty and precipitous, and at one point reaches a height of 17,300 feet.
The Astronomy of Milton's 'Paradise Lost'|Thomas Orchard

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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.