Definition

Noun: 1. A unit of luminance in the centimeter-gram-second system: A lambert is a unit of measurement for the brightness (luminance) of a surface. It is defined as the luminance of a perfectly diffusing surface that emits or reflects light at a rate of one lumen per square centimeter. 2. A surname, notably of Constant Lambert: Refers to an English composer and conductor (1905–1951).

Usage Examples

• Noun (Unit of Measurement):
  • The brightness of the old projector screen was measured at 3 lamberts.
  • This standard specifies that the surface must not exceed a luminance of 0.5 lambert.
• Noun (Proper Name):
  • The ballet "Horoscope" was composed by Lambert.
  • Scholars study the works of Lambert to understand 20th-century British music.

Advanced Usage

• The lambert (L) is a non-SI unit. In the International System of Units (SI), luminance is measured in candelas per square meter (cd/m²), also called a nit. One lambert is equal to approximately 3183.1 candelas per square meter.
• It is primarily used in older scientific and technical literature, particularly in the fields of photometry and radiometry.

Variants and Related Words

• Millilambert (mL): A subunit equal to one-thousandth of a lambert, sometimes used for more convenient numbers when measuring lower levels of luminance.

Synonyms

• For the unit: (No direct synonym, but the SI equivalent is) candela per square meter (cd/m²), nit.

Notes on Different Meanings

The two meanings are distinct and belong to different contexts: 1. The scientific unit is a common noun and is not capitalized unless starting a sentence. 2. The surname is a proper noun and is always capitalized. Context (e.g., discussing physics vs. music history) will always clarify which meaning is intended.

Noun

1. English composer and conductor (1905-1951)
2. a cgs unit of illumination equal to the brightness of a perfectly diffusing surface that emits or reflects one lumen per square centimeter