langley
C2Technical / Scientific
Definition
Meaning
A unit for measuring solar radiation, equal to one calorie per square centimetre.
Used primarily in meteorology and climatology to quantify the amount of solar energy reaching a given area; also a surname and place name.
Linguistics
Semantic Notes
A highly specialised term largely confined to atmospheric science and solar energy fields. The common noun is not used in general conversation.
Dialectal Variation
British vs American Usage
Differences
No meaningful difference in usage. The term is equally rare in both dialects outside technical contexts.
Connotations
Solely scientific; carries no regional or cultural connotations.
Frequency
Extremely low frequency in all registers except specific scientific literature.
Vocabulary
Collocations
Grammar
Valency Patterns
a measurement of X langleysan irradiance of Y langleys per minuteVocabulary
Synonyms
Strong
Neutral
Weak
Usage
Context Usage
Business
Virtually never used.
Academic
Used in papers on climatology, meteorology, and solar physics.
Everyday
Not used.
Technical
The primary context; used in technical specifications and scientific measurements.
Examples
By CEFR Level
- Solar radiation is sometimes measured in a unit called the langley.
- The map showed the incoming radiation in langleys.
- The average solar constant is approximately 2.0 langleys per minute.
- Historical climate models often used langleys per day to quantify insolation.
Learning
Memory Aids
Mnemonic
Think of 'Langley' as a person (like a scientist) who counts calories (energy) falling on every square centimetre of the earth.
Conceptual Metaphor
SOLAR ENERGY IS A MEASURABLE QUANTITY (counted in units named after a person).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating it as a general 'unit of light' or confusing it with 'люмен' (lumen). It is specifically for solar thermal energy, not brightness.
Common Mistakes
- Using it as a general term for sunlight.
- Misspelling as 'Langly' or 'Langleigh'.
- Confusing it with the place name or surname in contexts requiring the scientific unit.
Practice
Quiz
What does the unit 'langley' measure?
FAQ
Frequently Asked Questions
No, it is a highly specialised scientific term with very limited use outside meteorology and climatology.
It is named after the American astrophysicist Samuel Pierpont Langley (1834–1906).
Its use has declined in favour of SI units like watts per square metre (W/m²), but it may appear in older literature or specific contexts.
No, it functions exclusively as a noun (a count noun: one langley, two langleys).