annulus: meaning, definition, pronunciation and examples
C2Technical/Scientific
Quick answer
What does “annulus” mean?
A ring-shaped object, area, or structure.
Audio
Pronunciation
Definition
Meaning and Definition
A ring-shaped object, area, or structure.
In mathematics, the region between two concentric circles; in biology, a ring-shaped structure in plants or animals; in engineering, a ring-shaped component or space.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage. Slight preference for 'annulus' in UK engineering contexts, while US may occasionally use 'ring' or 'washer' in non-technical descriptions.
Connotations
Neutral, precise, geometric/technical.
Frequency
Equally rare in both dialects, confined to specialist fields.
Grammar
How to Use “annulus” in a Sentence
the annulus of [noun]an annulus between [noun] and [noun]form an annulusVocabulary
Collocations
Examples
Examples of “annulus” in a Sentence
adjective
British English
- annular eclipse
- annular space
American English
- annular region
- annular component
Usage
Meaning in Context
Business
Virtually never used.
Academic
Common in mathematics (geometry), fluid dynamics, botany (fern spore rings), and anatomy (e.g., heart valves).
Everyday
Extremely rare. Would be replaced by 'ring', 'washer', or 'doughnut shape'.
Technical
The primary register. Used with precise geometric or structural meaning.
Watch out
Common Mistakes When Using “annulus”
- Using 'annulus' in everyday speech.
- Pronouncing it as /əˈnuːləs/.
- Using the wrong plural ('annuluses' is acceptable but 'annuli' is more common in science).
FAQ
Frequently Asked Questions
No, it is a technical term used almost exclusively in mathematics, science, and engineering.
'Annulus' is a precise geometric term for the area between two circles. 'Ring' is a general word and can be solid (like a wedding ring) or refer to the annulus shape.
In British English: /ˈænjʊləs/ (AN-yu-luhs). In American English: /ˈænjələs/ (AN-yuh-luhs).
The Latin plural 'annuli' (/ˈænjʊlaɪ/ or /ˈænjəlaɪ/) is standard in technical writing. The English plural 'annuluses' is also acceptable.
A ring-shaped object, area, or structure.
Annulus is usually technical/scientific in register.
Phrases
Idioms & Phrases
- “None”
Learning
Memory Aids
Mnemonic
Think of 'annual' rings in a tree trunk – an 'annulus' is like a single ring.
Conceptual Metaphor
CONTAINMENT IS A RING (e.g., 'the fluid is confined within the annulus').
Practice
Quiz
In which field is the term 'annulus' LEAST likely to be used?