Epsilon 9487 224544437 2008-07-09T09:51:01Z 121.72.160.97 /* Fictional names */ {{otheruses4|Greek epsilon|Latin epsilon|ɛ}} {{wiktionarypar2|Ε|ε}} {{Table_Greekletters|letter=epsilon}} '''Epsilon''' (uppercase '''Ε''', lowercase '''ε'''; {{lang-el|Έψιλον}}) is the fifth letter of the [[Greek alphabet]], corresponding phonetically to a [[close-mid front unrounded vowel]] /e/. In the system of [[Greek numerals]] it has a value of 5. It was derived from the [[Phoenician alphabet|Phoenician letter]] [[He (letter)|He]] [[Image:phoenician he.png|20px|He]]. Letters that arose from Epsilon include the Roman [[E]] and Cyrillic [[Ye (Cyrillic)|Ye]]. "Epsilon" ({{polytonic|ἒ ψιλόν}}, "simple e") was coined in the Middle Ages to distinguish the letter from the [[Greek orthography|diphthong αι]], which started being pronounced the same way during the period of [[New Testament Greek]]. The standard symbol for lowercase epsilon is the '''lunate epsilon [[ϵ]]''' (\epsilon, <math>\epsilon\,</math>, in [[LaTeX]]), which has its origins in Medieval Greek. In mathematical notation, the minuscule '''open e''' symbol '''[[ɛ]]''' (\varepsilon, <math>\varepsilon</math>, in LaTeX) from the extended [[Latin alphabet]] is often used interchangeably with the '''lunate epsilon.''' The lunate epsilon ϵ is not to be confused with the set symbol <math>\in</math> or falsely recognized as the lunate version [[Σ]]. ==Symbol== The upper-case Epsilon is not a commonly-used symbol outside of the Greek language because of its similarity to the Roman letter [[E]]. The lower-case epsilon, '''[[ε]]'''/'''[[ϵ]]''', or open e, '''[[ɛ]]''', (see above) is used as the symbol for: * In mathematics (particularly [[calculus]]), an arbitrarily (or nearly so) small positive quantity is commonly denoted ε; see [[limit (mathematics)|limit]]. ** By analogy with this, the late mathematician [[Paul Erdős]] also used the term "epsilons" to refer to children ([[Paul Hoffman|Hoffman]] 1998, p. 4). * In mathematics, the [[Levi-Civita symbol]]. * In mathematics, to represent the [[dual number]]s: a + bε, with ε<sup>2</sup>=0 and ε≠0. * In mathematics, sometimes used to denote the [[Heaviside step function]] * In [[set theory]], the [[epsilon nought|limit ordinal]] of the sequence <math>\omega,\omega^{\omega},\omega^{\omega^{\omega}},\dots</math>. * In computing, the [[precision]] of a numeric data type and floating-point [[machine epsilon]]. * In [[computer science]], the [[String (computer science)|empty string]], though different writers use a variety of other symbols for the empty string as well, including the lower case Greek letter [[lambda]]. * In physics, the [[permittivity]] of a medium. * In physics/electronics, the [[Electromotive force|EMF]] of a circuit * In physics, the [[Strain (materials science)|strain]] of a material (A ratio of extensions). * In [[automata theory]], a transition that involves no shifting of an input symbol. * In [[astronomy]], the fifth brightest (usually) star in a [[constellation]]. ''See'' [[Bayer designation]]. * In the [[International Phonetic Alphabet]], the [[open-mid front unrounded vowel]], (but generally written ɛ instead of ε) as in the English word "pet" (/pɛt/) * In [[astronomy]], Epsilon is the name for Uranus' most distant and most visible ring. * In [[chemistry]], the [[molar extinction coefficient]] of a [[chromophore]]. * In [[economics]], ε refers to [[elasticity (economics)|elasticity]]. ===Fictional names=== * In the popular web series "[[Red vs. blue]]", Epsilon is the name of the AI assigned to freelancer Washington. * ''Epsilon in Malaysian Pale'' is the name of the second solo album released by [[Tangerine Dream]] leader [[Edgar Froese]] in [[1975]]. * Epsilon is also an [[Australian]] light-powered female-looking [[robot]] that fought [[Pluto (manga)|Pluto]] in an episode of [[Astro Boy (2003)|Astro Boy]]. * ''Epsilon Eridani III'' is the planet that the spacestation [[Babylon 5]] orbited in the eponymous [[science fiction|sci-fi]] television series. * [[E-104 Epsilon]] is also the name of a robot in [[Sonic Adventure]]. * "Epsilon 9" is the name of the Federation space station consumed by the V'ger cloud in [[Star Trek: The Motion Picture]]. * Epsilon is the name of an unlockable creature in the game [[Monster Rancher 2]] * In Greek it is used for [[Epsilon Team]]. * "Epsilon Mirror" is the name of one of Aika's moves in the video game [[Skies of Arcadia]]. * ''Epsilon'' is the leader of the Rebellion in [[Mega Man X: Command Mission]] * "The Epsilon Program" is a mysterious [[cult]] in the video game [[Grand Theft Auto: San Andreas]] by Game Developer [[Rockstar North]]. This cult is thought to be based on [[Scientology]]. * The Epsilon Project is a fictional experiment mentioned in the [[Dreamcast]] and [[Xbox]] versions of [[Dead or Alive 2]] and is based around cloning. * Epsilon is the lowest of five social [[caste]]s in the [[Aldous Huxley]] novel ''[[Brave New World]]''. * "Plan Epsilon" was one of many plans to restore [[Doctor Doom]] to life in the event of his death, as shown in [[Fantastic Four]] issue no. 246, written by [[Stan Lee]]. * Epsilon-Eagle is the name of the protagonist in the [[Sega Mega Drive]] game [[Alien Soldier]]. * Epsilon was the name given to one of the ground support teams in the [[Sony Playstation]] game [[G-Police]] * Epsilon is the name of the newly resurrected Yuri Faction in the [[Yuri's Revenge]] mod [[Mental Omega]] ===Other uses=== *"Epsilon" is the name used by [[General Motors]] for the post-[[2003]] [[GM Epsilon platform|Epsilon platform]]. * [[EpsilonEuskadi]] carmaker <ref>[http://www.epsiloneuskadi.com/ EPSILON EUSKADI==JOAN VILLADELPRAT & SERGIO RINLAND & JORDI CATON==AZKOITIA (43º 10' 22'&#39; N - 2º 19' 26'&#39; O)<!-- Bot generated title -->]</ref> and [[EpsilonEuskadi LMP1]] car. *[[Hurricane Epsilon (2005)|Hurricane Epsilon]], a storm of the [[2005 Atlantic hurricane season]]. *"Epsilon Concepts" is the name of a national digital agency. == References == *[[Paul Hoffman|Hoffman, Paul]]; ''[[The man who loved only numbers]]''. Hyperion, 1998. ISBN 0-7868-6362-5. <References/> __NOTOC__ [[Category:Greek letters]] [[Category:Vowel letters]] [[als:Ε]] [[ar:إبسيلون (حرف إغريقي)]] [[arc:Ε]] [[ast:Epsilon]] [[br:Epsilon (lizherenn)]] [[bg:Епсилон]] [[ca:Èpsilon]] [[cy:Epsilon]] [[da:Epsilon]] [[de:Epsilon]] [[el:Έψιλον]] [[es:Ε]] [[eo:Epsilono]] [[ext:Éssilun]] [[eu:Epsilon (greko)]] [[fr:Epsilon]] [[ga:Eipsealón]] [[gd:Epsilon]] [[gl:Epsilon]] [[ko:Ε]] [[hr:Epsilon]] [[id:Epsilon]] [[is:Epsílon]] [[it:Epsilon (lettera)]] [[he:אפסילון]] [[ka:ეფსილონი (ასო)]] [[sw:Epsilon]] [[ht:Ε]] [[ku:Epsilon]] [[la:Epsilon]] [[lt:Epsilon (raidė)]] [[hu:Epszilon]] [[ms:Epsilon]] [[nah:Ε]] [[nl:Epsilon]] [[ja:Ε]] [[no:Epsilon]] [[nn:Epsilon]] [[nds:Epsilon]] [[pl:Epsilon]] [[pt:Ε]] [[ru:Эпсилон (буква)]] [[simple:Epsilon]] [[sk:Epsilon]] [[sl:Epsilon]] [[sh:Epsilon]] [[fi:Epsilon]] [[sv:Epsilon]] [[th:เอปไซลอน]] [[tr:Ε]] [[uk:Епсилон (літера)]] [[zh:Ε]]