Lambda (uppercase Λ, lowercase λ; Λάμβδα or Λάμδα, Lamda) is the 11th letter of the Greek alphabet. In the system of Greek numerals it has a value of 30. It was derived from the Phoenician letter Lamed . Letters that arose from Lambda include the Roman L and the Cyrillic letter El (Л, л). The ancient Grammarians and dramatists attest to a pronunciation of /laːbdaː/ (λάβδα) in classical times. In Modern Greek the name of the letter, Λάμδα, is pronounced [lamða]; the letter itself is pronounced [l] as with Latin L.
In early Greek alphabets, the shape and orientation of lambda varied. Most variants consisted of two straight strokes, one longer than the other, connected at their ends. The angle might be in the upper left, lower left ("Western" alphabets), or top ("Eastern" alphabets). Other variants had a vertical line with a horizontal or sloped stroke running to the right. With the general adoption of the Ionic alphabet, Greek settled on an angle at the top; the Romans, borrowing from Western alphabets, put the angle at the lower left.
Upper-case letter Λ
- The lambda particles in particle physics.
- The set of logical axioms in the axiomatic method of logical deduction in first-order logic.
- Used as a shield pattern by the Spartan army; it stood for Lakedaimon, the name of the region.
- The von Mangoldt function in number theory.
- In statistics, Wilks' lambda is used in multivariate analysis of variance (MANOVA) to compare group means on a combination of dependent variables.
- In spectral decomposition of matrices, a diagonal matrix of eigenvalues of the decomposed matrix.
- In computer science, the time window over which a process is observed for determining the working memory set for virtual memory management.
- In astrophysics, the likelihood that a small body will encounter a planet or dwarf planet leading to a deflection of a particular magnitude. An object with a large value is expected to have cleared its neighborhood, satisfying the current definition of a planet.
- In crystal optics, it is used to represent the period of a lattice.
- In NATO military operations, the Lambda symbol is painted on coalition force vehicles for identification.
- In Electrochemistry, denotes the Equivalent conductance of an electrolyte.
- In cosmology, the symbol for the cosmological constant.
Lower-case letter λ
Lambda, the word
- In anatomy, the lambda is that point on the skull where the two parietal bones and the occipital bone come together. The configuration of the sutures resembles an upper case lambda, and the suture between each parietal bone and the occipital bone is called the lambdoid suture.
- In programming languages such as Lisp and Python, lambda is an operator used to denote anonymous functions or closures, following lambda calculus usage.
- The language Unlambda is a functional programming language based upon combinatory logic, a simplification of the lambda calculus that does not involve the lambda at all, hence the un- prefix.
- An automotive oxygen sensor is also known as an O2 sensor, lambda probe, lambda sensor and lambda sound
- Lambda is used in art and photography to refer to a digital Type C print or the equipment used to produce it.
Lambda as a name
- The popular science fiction universe of Star Wars uses a transport vehicle known as the Lambda-class shuttle that when viewed forward has the shape of the lowercase lambda.
- Lambda is occasionally used in graphic design to represent stylized A's. Examples include the Disney movie Atlantis: The Lost Empire, the TV series Stargate SG-1 and Stargate Atlantis, the logo of the band Angels & Airwaves, the logo of the band Dream Theater, and the logo of electronics company Samsung. Conversely, the name of the band Λucifer (pronounced lucifer) is sometimes spelt Aucifer.
- Stargate SG-1 uses a modified upper-case lambda, with a small circle above the apex, to indicate Earth. This symbol has since become associated with the entire franchise.
- In the Half-Life series of computer games, the 'a' in the title is replaced by the lower case lambda symbol (λ is also the Roman cursive equivalent of the letter 'a'). Also, the Lambda Complex and the protagonist Gordon Freeman's suit both feature a lower-case lambda symbol. In Half-Life 2, the 'a' in the title is also replaced by the lower case lambda symbol and the symbol is also the logo for The Resistance. The robotic Dog and graffiti sprayed around City 17 also features the symbol. The main reason the lambda was used frequently throughout the series, is because in science and mathematics, the lambda symbol is the decay constant, a positive constant used to describe the rate of exponential decay in a half-life.
- In the book Otherland, Lambda is used to describe a huge Virtual Reality area of the Net known as the Lambda Mall which contains every shop on the net.
- As a bonus following the conclusion of the X-DAY manga, by Mizushiro Setona, the second book features a short tale entitled "The Last Supper." Its protagonist is a cow, genetically modified to have more human features, Lambda 26. The lambda character is tattooed on the outside of his right forearm.
- GM Lambda platform, a crossover SUV automobile platform from General Motors
- The name of the Nerds' fraternity in Revenge of the Nerds film series was Lambda Lambda Lambda, or "the Tri-Lambs." The logo consisted of three capital Lambda letters inside a triangle.
- In the popular anime series Full Metal Panic! A select few Arm Slaves possess the device called the Lambda Driver which can manifest emotional thought patterns into raw and devastating physical power. In Full Metal Panic! (primary series), Sousuke Sagara's ARX-7 "Arbalest" has a Lambda Driver (but due to Sagara's lack of experience, it only served to aid him most minimally and improved as time progressed). All oppositions Sousuke has faced where his enemy has used the Lambda Driver also exhibited great power, especially Gauron on three counts; and were all defeated using Arbalest's Lambda Driver.
- /lambda/ is the name of an ultra premium olive oil from Greece that is produced with Koroneiki olives, it is created through the process of common pressing, where carefully selected olives are hand-picked from the tree and pressed the same day.
- In the Sailor Moon manga, the character Sailor Cosmos claimed to have the ultimate "Lambda Power."
- Is the one of the main antagonists in Wild Arms: The 4th Detonator.
- In the video game Skies of Arcadia, the character Aika uses an attack known as Lambda Burst. In fact, all her attacks are based on Greek letters.
- Lambda is a name of an electrostatic headphone made by the audio company Stax Earspeakers. It is also a name of an amp made by Z-audio.
- Lambda Acid is also the name of a synthesis item in the online action RPG, Phantasy Star Universe.
- Lambda Ltd. is the name of a large technology company in the Custom Robo series of video games.
- The latest installment of the Guilty Gear series of games is called Guilty Gear XX Λ Core, commonly pronounced as "Guilty Gear Accent Core".
- Lambda Legal is a gay & lesbian legal advocacy group in the United States.
- Lambda Literary Awards is the name of a group of U.S. book awards presented annually for gay and lesbian literature.
- Lambda Particles is the name for the LGBT group at the Stanford Linear Accelerator Center.
- National LambdaRail is a research high-speed computer network.
- Lambda Americas is a manufacturer of power supplies that was founded in 1948.
- Hyundai Motors uses Lambda to identify their 3.8 liter V6 engine.
- Lambda is the name used by Durst for a series of digital printers using LED's to print directly onto Silver Halide Photographic paper.
- The progressive metal band Dream Theater uses the capital Lambda (as well as capital Phi and capital Mu) in their wordmark known as the "Majesty Symbol"