What does "annulus" mean?
A ring- or donut-shaped area, object, or structure.
Annulus
/ˈænjʊləs/ noun
noun ·Moderate ·College level
Meaning at a glance
- Primary sense: A ring- or donut-shaped area, object, or structure.
- Grammar: annulus is listed as noun.
- Nearest alternatives: ring, anchor ring, annular aperture, annulet.
- Useful contrasts: center, disk, solid disk.
- Usage evidence: But by the knots I am ſpeaking of, may it pleaſe your reverences to believe, that I mean good, honeſt, deviliſh tight, hard knots, made bona fide, as Obadiah made his;—in vvhich there is no quibbling proviſion made by the duplication and return of the tvvo ends of the ſtrings through the annulus or nooſe made by the ſecond implication of them— […]
How to use "annulus"
- Start with the primary definition, then check the part of speech before placing the word in a sentence.
- Compare nearby synonyms to make sure "annulus" carries the exact meaning, tone, and strength you need.
- Use the example sentence as a context check. If your sentence uses the word differently, confirm that the grammar still fits.
Meaning check
- Does the word fit the sentence's grammar?
- Does it match the intended tone rather than only the dictionary definition?
- Would a simpler synonym be clearer for the reader?
- Is there enough surrounding context to prevent ambiguity?
Source and review context
This entry combines structured lexical data with WordToolSet review checks. Definitions, examples, synonyms, and usage notes may come from different source tables, so the page is designed to show evidence from more than one angle before you rely on "annulus" in a final draft.
If a word has several senses, prefer the sense that matches your sentence's grammar and surrounding context. A correct definition can still be the wrong choice when the sentence needs a different register, emphasis, or level of specificity.
Before you rely on this definition
Read the first definition as a starting point, then check the example, synonyms, and part of speech before treating "annulus" as the right word for your sentence.
If your draft is formal, technical, persuasive, or sensitive, compare "annulus" with a nearby alternative so the final choice matches both meaning and reader expectation.
Compare nearby meanings
- Use synonyms when you need a softer, stronger, simpler, or more specific word.
- Use antonyms to check the boundary of the meaning and avoid accidental contrast.
- Use the example sentence to confirm the word behaves naturally in context.
- Keep the original wording when a replacement adds complexity without improving precision.
Definition decision workflow
1. Identify the role
Check whether "annulus" is acting as noun in your sentence. A definition is only useful when the grammar matches the way the word is being used.
2. Test the nearest option
Compare it with "ring" and other nearby choices to see whether the sentence needs a softer, stronger, or more familiar word.
3. Confirm with context
Use the example sentence below as an evidence check, then read your own sentence out loud to catch tone or rhythm problems.
Review note: Definition pages are checked for source coverage, sentence evidence, synonym support, and editorial insight before they are treated as approval-ready pages. If the evidence is too thin, the page remains available to users but is kept out of the approval-facing indexed inventory.
Final meaning check
Before publishing a sentence with "annulus", ask whether the word helps the reader understand the idea faster. A precise word should reduce confusion, not simply make the sentence look more polished.
When the definition, synonym evidence, and example context point in the same direction, the word is usually a safer choice. When they conflict, revise the sentence or choose a clearer alternative.
Definitions
Noun
- 1 A ring- or donut-shaped area, object, or structure.
"But by the knots I am ſpeaking of, may it pleaſe your reverences to believe, that I mean good, honeſt, deviliſh tight, hard knots, made bona fide, as Obadiah made his;—in vvhich there is no quibbling proviſion made by the duplication and return of the tvvo ends of the ſtrings through the annulus or nooſe made by the ſecond implication of them— […]"
- 2 (Fungi) a remnant of the partial veil that in mature mushrooms surrounds the stem like a collar wordnet
- 3 A ring of fibrous tissue; specifically (cardiology), such a ring around an opening of a heart valve, to which the valve leaflets and muscle fibres of the atria and ventricles are attached; an annulus fibrosus cordis.
- 4 a toroidal shape wordnet
- 5 A ring of light in a celestial body, especially when caused by an annular eclipse (for example, when the Sun and Moon are in line with the Earth, but the Moon does not completely cover the Sun's disc).
Show 6 more definitions
- 6 A structure surrounding a sporangium (or part of it) which shrinks and causes it to rupture for spore dispersal; specifically, in a fern: a structure around about two-thirds of the sporangium consisting of differentially thick-walled cells which dry and distort the sporangium; and in a moss: a complete ring of cells around the tip of the sporangium which dissolves to cause the tip to detach.
- 7 The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom.
- 8 A dark ring on a fish's scale that is formed when a fish's growth rate slows down in the winter due to low food intake and the scale's circuli move closer to one another. The dark ring is used to estimate the fish's age, approximately one year per annulus.
- 9 The region in a plane between two concentric circles of different radii.
- 10 Any topological space homeomorphic to the region in a plane between two concentric circles of different radii.
- 11 In a well such as an oil well or water well: the space between a pipe or tube and any pipe, tube, casing, or sides of a hole surrounding it.
"Pressure balance is obtained by the air pressure in the cylinder operating on a supplementary piston in the buffer piston head, transmitting pressure to a small quantity of oil which is ported to an annulus between the buffer piston seals and the cylinder wall, so that the seal is always under opposing pressures; oil on one side and air on the other."
Synonyms
All synonymsExample
"But by the knots I am ſpeaking of, may it pleaſe your reverences to believe, that I mean good, honeſt, deviliſh tight, hard knots, made bona fide, as Obadiah made his;—in vvhich there is no quibbling proviſion made by the duplication and return of the tvvo ends of the ſtrings through the annulus or nooſe made by the ſecond implication of them— […]"
Common questions
What is a synonym for "annulus"?
Common synonyms include: ring, anchor ring, annular aperture, annulet, areola, aureole.
How do you use "annulus" in a sentence?
But by the knots I am ſpeaking of, may it pleaſe your reverences to believe, that I mean good, honeſt, deviliſh tight, hard knots, made bona fide, as Obadiah made his;—in vvhich there is no quibbling proviſion made by the duplication and return of the tvvo ends of the ſtrings through the annulus or nooſe made by the ſecond implication of them— […]
How do you pronounce "annulus"?
Pronounced /ˈænjʊləs/.
Etymology
Learned borrowing from Medieval Latin ānnulus, a misspelling of Latin ānulus (“ring, especially one worn on a finger”), from ānus (“ring”) (possibly from Proto-Indo-European *h₁eh₂-n-o- (“ring”), from an uncertain root) + -ulus (diminutive suffix). The plural form annuli is a learned borrowing from Medieval Latin ānnulī.