Epsilon (uppercase Ε, lowercase ε; _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 numeralsit has a value of 5. It was derived from the Phoenician letter He .
"Epsilon" (polytonic|ἒ ψιλόν, "simple e") was coined in the Middle Ages to distinguish the letter from the 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, , in
LaTeX), which has its origins in Medieval Greek.
In mathematical notation, the minuscule open e symbol
ɛ(varepsilon, , in LaTeX) from the extended Latin alphabetis often used interchangeably with the lunate epsilon.
The lunate epsilon ϵ is not to be confused with the set symbol or falsely recognized as the lunate version
Upper case: character code 0395Lower case: character code 03B5
The upper-case Epsilon is not a commonly-used symbol outside of the Greek language because of its similarity to the Roman letter
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.
** By analogy with this, the late mathematician
Paul Erdősalso used the term "epsilons" to refer to children (Hoffman 1998, p. 4).
* In mathematics, the
* In mathematics, to represent the
dual numbers: a + bε, with ε2=0 and ε≠0.
* In mathematics, sometimes used to denote the
Heaviside step function
set theory, the limit ordinal of the sequence .
* In computing, the
precisionof a numeric data type and floating-point machine epsilon.
computer science, the 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
permittivityof a medium.
* In physics/electronics, the EMF of a circuit
* In physics, the strain of a material (A ratio of extensions).
automata theory, a transition that involves no shifting of an input symbol.
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/)
astronomy, Epsilon is the name for Uranus' most distant and most visible ring.
chemistry, the molar extinction coefficientof a chromophore.
economics, ε refers to elasticity.
* 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 Dreamleader Edgar Froesein 1975.
* Epsilon is also an
Australianlight-powered female-looking robotthat fought Pluto in an episode of Astro Boy.
* "Epsilon Eridani III" is the planet that the spacestation
Babylon 5orbited in the eponymous sci-fi television series.
E-104 Epsilonis 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 .
* Epsilon is the name of an unlockable creature in the game
Monster Rancher 2
* In Greek it is used for
* "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
* "The Epsilon Program" is a mysterious
cultin the video game by Game Developer Rockstar North. This cult is thought to be based on Scientology.
* The Epsilon Project is a fictional experiment mentioned in the
Dreamcastand Xboxversions of Dead or Alive 2and is based around cloning.
* Epsilon is the lowest of five social
castes in the Aldous Huxleynovel " Brave New World".
* "Plan Epsilon" was one of many plans to restore
Doctor Doomto life in the event of his death, as shown in Fantastic Fourissue no. 246, written by Stan Lee.
* Epsilon-Eagle is the name of the protagonist in the
Sega Mega Drivegame Alien Soldier.
* Epsilon was the name given to one of the ground support teams in the
Sony Playstationgame G-Police
* Epsilon is the name of the newly resurrected Yuri Faction in the
Yuri's Revengemod Mental Omega
*"Epsilon" is the name used by
General Motorsfor the post-2003 Epsilon platform.
EpsilonEuskadicarmaker [ [http://www.epsiloneuskadi.com/ EPSILON EUSKADI=JOAN VILLADELPRAT & SERGIO RINLAND & JORDI CATON=AZKOITIA (43º 10' 22' N - 2º 19' 26' O) ] ] and EpsilonEuskadi LMP1car.
*Hurricane Epsilon, a storm of the
2005 Atlantic hurricane season.
*"Epsilon Concepts" is the name of a national digital agency.
*Hoffman, Paul; "
The man who loved only numbers". Hyperion, 1998. ISBN 0-7868-6362-5.
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