lambert

Low
UK/ˈlæmbət/US/ˈlæmbɚt/

Technical / Scientific

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Definition

Meaning

A unit of luminance (or luminous intensity per unit area) in the centimetre-gram-second (CGS) system.

The name can also refer to a surname of English and French origin, and, rarely, as an archaic given name.

Linguistics

Semantic Notes

As a scientific unit, it is named after Johann Heinrich Lambert. It is largely obsolete, having been superseded by the candela per square metre (cd/m²) in the SI system.

Dialectal Variation

British vs American Usage

Differences

No significant difference in usage; it's a technical, standardized term.

Connotations

Purely technical, historical in scientific context.

Frequency

Extremely rare in both dialects outside of historical or specialized physics/optics contexts.

Vocabulary

Collocations

strong
a lambert of luminanceper square lambert
medium
the unit lambertmeasure in lamberts
weak
brightness of a lambertold lambert system

Grammar

Valency Patterns

The screen emitted a luminance of X lamberts.It was measured in lamberts.

Vocabulary

Synonyms

Strong

candela per square metre (SI equivalent)

Neutral

luminance unitCGS unit

Weak

brightness measurephotometric unit

Usage

Context Usage

Business

Virtually never used.

Academic

Only in historical discussions of photometry or optics.

Everyday

Not used.

Technical

Used occasionally in older technical literature or for specific calculations in photometry.

Examples

By CEFR Level

B1
  • The old book mentioned a measurement called a lambert.
B2
  • In the CGS system, luminance can be expressed in lamberts, though it's rarely used today.
C1
  • The physicist converted the legacy data from lamberts to the modern SI unit of candelas per square metre.

Learning

Memory Aids

Mnemonic

Think of LAMB + BRIGHT. A LAMBert is an old measure of how bright something is, named after Mr. Lambert.

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

  • Do not confuse with the name/surname 'Ламберт'.
  • It is not a common noun in Russian; the concept is 'ламберт' (unit) or more commonly 'кандела на квадратный метр'.

Common Mistakes

  • Using it as a current unit instead of candela per square metre.
  • Capitalising it incorrectly in the middle of a sentence when referring to the unit (it is lowercase).

Practice

Quiz

Fill in the gap
Before the adoption of the SI system, photometric luminance was sometimes measured in .
Multiple Choice

What is a 'lambert'?

FAQ

Frequently Asked Questions

No, it is largely obsolete and has been replaced by the SI unit candela per square metre (cd/m²).

It was named after the Swiss polymath Johann Heinrich Lambert (1728–1777).

Yes, it is a common English and French surname, and historically a given name, unrelated to the scientific unit.

1 lambert = (1/π) × 10^4 candelas per square metre, approximately 3183.1 cd/m².