lux
C1/C2Formal, Technical, Poetic/Literary
Definition
Meaning
The SI unit of illuminance, equal to one lumen per square metre.
A measure of the intensity of light falling on or illuminating a surface; figuratively, used in poetic or technical contexts to denote a brilliant or splendid quality.
Linguistics
Semantic Notes
Primarily a technical term in physics and engineering. Its non-technical use is rare, archaic, or deliberately literary, often implying a radiant or splendid light.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. The term is equally technical in both variants.
Connotations
In both regions, the primary connotation is scientific precision. Any literary use is markedly elevated or archaic.
Frequency
Extremely low frequency in general discourse, used almost exclusively in scientific, engineering, and lighting design contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
[Number] luxan illuminance of [Number] luxmeasured in luxVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[No common idioms. Term is technical.]”
Usage
Context Usage
Business
Used in specifications for workplace lighting, retail display lighting, or architectural design proposals (e.g., 'The office standard requires 500 lux on work surfaces.').
Academic
Used in physics, engineering, architecture, and photography papers to quantify light exposure (e.g., 'Seed germination was tested under 2000 lux.').
Everyday
Virtually never used in everyday conversation. A layperson might say 'brightness' or 'light level'.
Technical
The primary context. Used in lighting design, photometry, horticulture (grow lights), cinematography, and occupational health standards.
Examples
By Part of Speech
verb
British English
- [No standard verb form]
American English
- [No standard verb form]
adverb
British English
- [No standard adverb form]
American English
- [No standard adverb form]
adjective
British English
- [No standard adjective form. 'Lux' is a noun.]
American English
- [No standard adjective form. 'Lux' is a noun.]
Examples
By CEFR Level
- This room is very bright.
- We need more light here.
- The light in this office is good for reading.
- Plants need enough light to grow.
- The photographer measured the light before taking the portrait.
- Regulations specify a minimum level of illumination for factories.
- The laboratory requires an illuminance of at least 750 lux on all benches.
- Modern smartphone cameras can function in lighting as low as 1 lux.
Learning
Memory Aids
Mnemonic
Think of 'LUX'ury cars with bright, brilliant headlights. The unit 'lux' measures how brilliant that light is on a surface.
Conceptual Metaphor
LIGHT IS A MEASURABLE QUANTITY / ILLUMINATION IS A COVERING (as lux measures light 'falling on' a surface).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Не путать с брендом моющих средств 'Lux'.
- Не является прямым переводом слова 'люкс' (роскошь), хотя исторически связано с латинским 'lux' (свет). В техническом контекте это единица измерения.
Common Mistakes
- Using 'lux' interchangeably with 'lumen' (lumens measure total light output; lux measures light received per area).
- Pronouncing it /luːks/ (like 'Luke's') instead of the correct /lʌks/ (like 'lucks').
- Using it in non-technical contexts where 'light' or 'brightness' would be natural.
Practice
Quiz
What does 'lux' specifically measure?
FAQ
Frequently Asked Questions
No, it is a specialist term used primarily in science, engineering, and lighting design. It is very rare in everyday English.
A lumen measures the total amount of visible light emitted by a source (its luminous flux). A lux measures how much of that light lands on a specific surface area (luminous flux per square metre). One lux equals one lumen per square metre.
No. While the Latin root 'lux' means 'light', and the idea of 'light' can be associated with splendour, the English word 'luxury' comes from a different Latin root ('luxuria' meaning excess). The unit 'lux' is never used to mean luxury.
It is pronounced /lʌks/, rhyming with 'tux' (as in tuxedo) or 'ducks'. The vowel sound is the same as in 'luck'.