annulus
Americannoun
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a ring; a ringlike part, band, or space.
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Geometry. the space between two concentric circles on a plane.
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the veil remnant on a mushroom stalk.
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a growth ring, as on the cross section of a tree trunk, that can be used to estimate age.
noun
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the area between two concentric circles
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a ring-shaped part, figure, or space
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A ringlike figure, part, structure, or marking, such as a growth ring on the scale of a fish.
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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.
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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.
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The figure bounded by and containing the area between two concentric circles.
Other Word Forms
Etymology
Origin of annulus
1555–65; < Latin, variant of ānulus, equivalent to ān ( us ) ring + -ulus -ule
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Shells have always played an important role in Mauritian culture - the Monetaria annulus, commonly known as gold ring cowrie, is a gift of love or luck.
From BBC • Dec. 28, 2021
The circular annulus sector R bounded by the circles 4x2 + 4y2 = 1 and 9x2 + 9y2 = 64, the line x = y 3, and the y-axis is shown in the following figure.
From Textbooks • Mar. 30, 2016
The red primer annulus makes me lean towards Iran, but this example could quite easily have come from either country.
From New York Times • Nov. 7, 2012
Its tubercles and soft tissues were inflamed, and the annulus fibrosus of its disks was the color of bad teeth.
From The New Yorker • Feb. 28, 2011
The stem is equal, bulbous, floccose mealy above, stuffed or hollow, white, the annulus slight, evanescent.
From The Mushroom, Edible and Otherwise Its Habitat and its Time of Growth by Hard, Miron Elisha
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
