# lambda

/ˈɫæmdə/ (US) · /lˈæmbdɐ/ (UK)

Source: https://englishreference.com/word/lambda
Updated: 2026-08-27

## Senses

### 1. Greek letter

noun · CEFR B2

the eleventh letter of the Greek alphabet.

For teachers: the eleventh letter of the Greek alphabet, represented as Λ (uppercase) or λ (lowercase).

- The professor wrote the Greek letter lambda on the blackboard.
- The student struggled to distinguish between the handwritten lambda and other similar characters in the ancient manuscript.

### 2. wavelength

noun · CEFR C1 · Technical

a symbol used in physics to represent the length of a wave.

For teachers: the standard symbol (λ) used in physics to denote wavelength, particularly in optics and acoustics.

- In this equation, lambda represents the wavelength of the light.
- The experiment required precise measurement of the lambda value to determine the refractive index of the new composite material.

### 3. programming function

noun · CEFR C1 · Technical

a small, simple function in computer code that does not have a name.

For teachers: an anonymous function in computer programming, often used for short-lived operations or as arguments to higher-order functions.

- You can use a lambda to sort the list without writing a full function.
- The developer refactored the code by replacing the named helper function with a concise lambda expression to improve readability.

### 4. cosmological constant

noun · CEFR C2 · Technical

a symbol for the energy density of space in the universe.

For teachers: the symbol (Λ) for the cosmological constant in Einstein's field equations of general relativity.

- Scientists use lambda to talk about how the universe is expanding.
- The precise value of lambda remains one of the most significant questions in modern physical cosmology.

### 5. finance/options

noun · CEFR C2 · Technical

a measure of how much an option's price changes compared to the asset it is based on.

For teachers: a measure of leverage in options trading, representing the percentage change in option value relative to a percentage change in the underlying price.

- The trader checked the lambda to see how risky the investment was.
- High lambda values indicate significant leverage, which can amplify both gains and losses in a volatile market environment.

### 6. anatomy/skull

noun · CEFR C2 · Technical

the point on the back of the skull where two bone lines meet.

For teachers: the craniometric point at the junction of the sagittal and lambdoid sutures.

- The doctor examined the lambda on the patient's X-ray.
- The forensic anthropologist identified the lambda to help determine the age and structural integrity of the skeletal remains.

## Examples

- The scientist used the Greek letter lambda to represent the wavelength.
- In functional programming, a lambda allows you to define a small function without giving it a specific name.
- The physicist calculated the precise value of lambda to determine how the light wave would refract through the experimental lens.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.