What does lambda mean?
Lambda is the name of the eleventh letter of the Greek alphabet, represented by Λ in uppercase and λ in lowercase. It is also one of the standard terms used in computer science for an anonymous function: a function created without being given a name and passed directly to another function or stored as a value. Such functions are described as lambda expressions, and lambda calculus is an influential mathematical framework associated with the development of theoretical computing. The name has a longer history as a technical symbol in physics, where λ commonly denotes wavelength and can also refer to a lambda baryon in particle physics. Context largely determines the intended sense. Outside specialist writing, people encounter lambda most often as the name of a Greek letter or as a term in programming. Its combination of Greek and mathematical heritage makes it especially useful for discussing both language, computation, and the physical sciences.
nounLambda is the name of the eleventh letter of the Greek alphabet, represented by Λ or λ. In computing, it denotes an anonymous function, and in physics the symbol λ commonly represents wavelength or refers to a lambda particle.
- In computing, an anonymous function that can be passed as a value and used without being assigned a name.
- The name of the eleventh letter of the Greek alphabet, represented by the uppercase Λ and lowercase λ.
- In physics, the symbol λ used to represent wavelength and certain other physical quantities.
- In particle physics, shorthand for a lambda baryon, a subatomic particle containing an up or down quark and a strange quark.
"The lambda passed to the function performs a calculation without needing a separate name."
"The lambda sorts each item before returning it to the caller."
"Lambda is the eleventh letter of the Greek alphabet."
The standard plural is lambdas, although technical prose often uses a construct such as lambda expressions when referring to several functions.
"The library provides several useful lambdas."
A Greek letter became a cornerstone of computer science: the lambda calculus introduced in the 1930s helped establish anonymous functions as fundamental objects in mathematical computing.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does lambda come from?
The English word comes through Latin from Ancient Greek λάμβδα, the Greek name for the letter whose forms are Λ and λ. The Greek letter name ultimately derives from Phoenician lamed, the ancestor of the similarly named letter in Hebrew and related alphabets. The Greek form also gave rise to terms such as lambdacism, while the shape of the Greek letter underlies the adjective lambdoid.
How lambda is actually used
The Greek-letter sense is standard in general English, while the anonymous-function sense is technical and especially common in computer science. In physics, λ often functions primarily as a symbol, so the surrounding context determines whether it denotes wavelength, a particle, or another measured quantity.