diameter
B1Neutral to formal; common in academic, technical, and general descriptive contexts.
Definition
Meaning
A straight line passing from side to side through the centre of a circle or sphere.
The length of such a line; used metaphorically to describe the width or thickness of any object, or the scope or scale of something abstract.
Linguistics
Semantic Notes
Primarily a geometric term. Its metaphorical use implies measurable breadth or comprehensiveness.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Minor differences in metaphorical application frequency.
Connotations
Neutral and technical in both varieties.
Frequency
Slightly more common in American technical writing (engineering, manufacturing).
Vocabulary
Collocations
Grammar
Valency Patterns
[number] in diametera diameter of [number]has/have a diameter of [number]Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Used in specifications for manufactured parts, pipes, cables, etc. (e.g., 'The contract specifies a minimum pipe diameter.')
Academic
Central to geometry, physics, engineering, and life sciences (e.g., 'They measured the diameter of the cell nucleus.')
Everyday
Describing the size of round objects like plates, trees, or pipes. (e.g., 'The pizza is nearly a foot in diameter.')
Technical
Precise measurement in fields like machining, astronomy ('angular diameter'), medicine ('lumen diameter').
Examples
By Part of Speech
noun
British English
- The diameter of the new water main is precisely 30 centimetres.
- One must calculate the diameter from the given circumference.
American English
- The tire's diameter is listed in the owner's manual.
- They drilled a hole with a diameter of half an inch.
Examples
By CEFR Level
- The plate has a diameter of about 25 cm.
- The tree trunk is one metre in diameter.
- To find the area, you need to know the circle's diameter or its radius.
- The engineer checked the diameter of the pipe before installation.
- The telescope can resolve objects with an angular diameter of less than one arcsecond.
- A slight increase in arterial diameter can significantly improve blood flow.
- The metaphorical diameter of the crisis extended far beyond the financial sector, affecting social and political institutions.
- The study correlated nanoparticle diameter with cellular uptake efficiency.
Learning
Memory Aids
Mnemonic
DIA-meter: Think of 'DIA' as 'across' (like in 'diagonal') + 'meter' (measure). It's the measure across a circle.
Conceptual Metaphor
SIZE IS DIAMETER (e.g., 'The scandal had a diameter that engulfed the entire government.' implying broad reach/comprehensiveness).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'диаметр' – it's a direct cognate, but ensure correct preposition use: '10 cm in diameter' not 'of diameter'.
Common Mistakes
- Using 'diameter' to mean 'radius'.
- Incorrect preposition: 'It has 10cm diameter.' instead of 'It has a diameter of 10cm' or 'It is 10cm in diameter.'
Practice
Quiz
Which sentence uses 'diameter' correctly?
FAQ
Frequently Asked Questions
The diameter is twice the length of the radius. The radius is the distance from the centre to the edge.
Yes, informally for roughly circular or cylindrical objects (e.g., 'the diameter of a tree trunk'). Technically, for non-circles, 'width', 'breadth', or 'major axis' is more precise.
Yes, 'diameter' is solely a noun. There is no verb 'to diameter'. The related adjective is 'diametral' or 'diametric'.
Stress is on the second syllable: dy-AM-et-er. The first syllable rhymes with 'die' or 'my'.
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