Epsilon
Encyclopedia
Epsilon is the fifth letter of the Greek alphabet
Greek alphabet
The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...

, corresponding phonetically to a close-mid front unrounded vowel
Close-mid front unrounded vowel
The close-mid front unrounded vowel, or high-mid front unrounded vowel, is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ....

/e/. In the system of Greek numerals
Greek numerals
Greek numerals are a system of representing numbers using letters of the Greek alphabet. They are also known by the names Ionian numerals, Milesian numerals , Alexandrian numerals, or alphabetic numerals...

it has a value of 5. It was derived from the Phoenician letter
Phoenician alphabet
The Phoenician alphabet, called by convention the Proto-Canaanite alphabet for inscriptions older than around 1050 BC, was a non-pictographic consonantal alphabet, or abjad. It was used for the writing of Phoenician, a Northern Semitic language, used by the civilization of Phoenicia...

He
He (letter)
He is the fifth letter of many Semitic alphabets, including Phoenician , Aramaic, Hebrew , Syriac and Arabic . Its sound value is a voiceless glottal fricative ....

. Letters that arose from Epsilon include the Roman E
E
E is the fifth letter and a vowel in the basic modern Latin alphabet. It is the most commonly used letter in the Czech, Danish, Dutch, English, French, German, Hungarian, Latin, Norwegian, Spanish, and Swedish languages.-History:...

and Cyrillic Ye
Ye (Cyrillic)
Ye is a letter of the Cyrillic alphabet. In some languages this letter is called E.It commonly represents the vowel or , like the pronunciation of ⟨e⟩ in "yes".Ye is romanized using the Latin letter E....

.

The name "epsilon" was coined in the Middle Ages to distinguish the letter from the digraph
Digraph (orthography)
A digraph or digram is a pair of characters used to write one phoneme or a sequence of phonemes that does not correspond to the normal values of the two characters combined...

αι, a former diphthong
Diphthong
A diphthong , also known as a gliding vowel, refers to two adjacent vowel sounds occurring within the same syllable. Technically, a diphthong is a vowel with two different targets: That is, the tongue moves during the pronunciation of the vowel...

that had come to be pronounced the same as epsilon.

The uppercase form of epsilon looks essentially identical to Latin E. The lowercase version has two typographical variants, both inherited from medieval Greek handwriting
History of the Greek alphabet
The history of the Greek alphabet starts with the adoption of Phoenician letter forms and continues to the present day. This article concentrates on the early period, before the codification of the now-standard Greek alphabet....

. One, the most common in modern typography and inherited from medieval minuscule, looks like an inverted "3". The other, also known as lunate
Lunate
Lunate is a term meaning crescent or moon-shaped. In the specialized terminology of lithic reduction, a lunate flake is a small, crescent-shaped flake removed from a stone tool during the process of pressure flaking....

or uncial epsilon and inherited from earlier uncial writing, looks like a semicircle crossed by a horizontal bar. While in normal typography these are just alternate font variants, they may have different meanings as mathematical symbols. Computer systems therefore offer distinct encodings for them. In Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

, the character U+03F5 "Greek lunate epsilon symbol" is provided specifically for the lunate form. In TeX
TeX
TeX is a typesetting system designed and mostly written by Donald Knuth and released in 1978. Within the typesetting system, its name is formatted as ....

, \epsilon () denotes the lunate form, while \varepsilon () denotes the inverted-3 form.

There is also a Latin epsilon or "open e", which looks similar to the Greek lowercase epsilon. It is encoded in Unicode as U+025B ("Latin small letter open e") and U+0190 ("Latin capital letter open e") and is used as an IPA phonetic symbol. The lunate or uncial epsilon has also provided inspiration for the euro sign (€).

The lunate epsilon (ϵ) is not to be confused with the set membership symbol (∈), nor should the Latin uppercase epsilon (Ɛ) be confused with the Greek uppercase sigma (Σ).

### Origin

The letter Ε was taken over from the Phoenician
Phoenician alphabet
The Phoenician alphabet, called by convention the Proto-Canaanite alphabet for inscriptions older than around 1050 BC, was a non-pictographic consonantal alphabet, or abjad. It was used for the writing of Phoenician, a Northern Semitic language, used by the civilization of Phoenicia...

letter He
He (letter)
He is the fifth letter of many Semitic alphabets, including Phoenician , Aramaic, Hebrew , Syriac and Arabic . Its sound value is a voiceless glottal fricative ....

(
) when Greeks first adopted alphabetic writing. In archaic Greek writing, its shape is often still identical to the Phoenician letter. Like other Greek letters, it could face either leftwards or rightwards , depending on the current writing direction, but just like in Phoenician, the horizontal bars always faced in the direction of writing. Archaic writing often preserves the Phoenician form with a vertical stem extending slightly below the lowest horizontal bar. In the classical era, through the influence of more cursive writing styles, the shape was simplified to the current E glyph.

### Sound value

The initial sound value of Ε was determined by the vowel occurring in the Phoenician letter name He, which made it a natural choice for being reinterpreted from a consonant symbol to a vowel symbol denoting an [e] sound. Besides its classical Greek sound value, the short /e/ phoneme, it could initially also be used for other [e]-like sounds. For instance, in early Attic
Attic Greek
Attic Greek is the prestige dialect of Ancient Greek that was spoken in Attica, which includes Athens. Of the ancient dialects, it is the most similar to later Greek, and is the standard form of the language studied in courses of "Ancient Greek". It is sometimes included in Ionic.- Origin and range...

before c.500 B.C., it was used also both for the long, open
Open-mid vowel
An open-mid vowel is a type of vowel sound used in some spoken languages. The defining characteristic of an open-mid vowel is that the tongue is positioned two-thirds of the way from an open vowel to a mid vowel...

/ɛː/, and for the long close
Close-mid vowel
A close-mid vowel is a type of vowel sound used in some spoken languages. The defining characteristic of a close-mid vowel is that the tongue is positioned two-thirds of the way from a close vowel to a mid vowel...

/eː/. In the former role, it was later replaced in the classic Greek alphabet by Eta
ETA
ETA , an acronym for Euskadi Ta Askatasuna is an armed Basque nationalist and separatist organization. The group was founded in 1959 and has since evolved from a group promoting traditional Basque culture to a paramilitary group with the goal of gaining independence for the Greater Basque Country...

(Η), which was taken over from eastern Ionic
Ionic Greek
Ionic Greek was a subdialect of the Attic–Ionic dialect group of Ancient Greek .-History:Ionic dialect appears to have spread originally from the Greek mainland across the Aegean at the time of the Dorian invasions, around the 11th Century B.C.By the end of the Greek Dark Ages in the 5th Century...

alphabets, while in the latter role it was replaced by the digraph
Digraph (orthography)
A digraph or digram is a pair of characters used to write one phoneme or a sequence of phonemes that does not correspond to the normal values of the two characters combined...

spelling ΕΙ.

### Epichoric alphabets

Some dialects used yet other ways of distinguishing between various e-like sounds.

In Corinth
Ancient Corinth
Corinth, or Korinth was a city-state on the Isthmus of Corinth, the narrow stretch of land that joins the Peloponnesus to the mainland of Greece, roughly halfway between Athens and Sparta. The modern town of Corinth is located approximately northeast of the ancient ruins...

, the normal function of Ε to denote /e/ and /ɛː/ was taken by a glyph resembling a pointed B , while Ε was used only for long close /eː/. The letter Beta
Beta
Beta is the second letter of the Greek alphabet. Beta or BETA may also refer to:-Biology:*Beta , a genus of flowering plants, mostly referred to as beets*Beta, a rank in a community of social animals...

, in turn, took the deviant shape .

In Sicyon
Sicyon
Sikyon was an ancient Greek city situated in the northern Peloponnesus between Corinth and Achaea on the territory of the present-day prefecture of Corinthia...

, a variant glyph resembling an X was used in the same function as Corinthian .

In Thespiai (Boeotia
Boeotia
Boeotia, also spelled Beotia and Bœotia , is one of the regional units of Greece. It is part of the region of Central Greece. It was also a region of ancient Greece. Its capital is Livadeia, the second largest city being Thebes.-Geography:...

), a special letter form consisting of a vertical stem with a single rightward-pointing horizontal bar was used for what was probably a raised
Close vowel
A close vowel is a type of vowel sound used in many spoken languages. The defining characteristic of a close vowel is that the tongue is positioned as close as possible to the roof of the mouth without creating a constriction that would be classified as a consonant.This term is prescribed by the...

variant of /e/ in pre-vocalic environments. This tack glyph was used elsewhere also as a form of "Heta", i.e. for the sound /h/.

### Glyph variants

After the establishment of the canonical classic Greek alphabet, new glyph variants for Ε were introduced through handwriting. In the uncial script (used for literary papyrus
Papyrus
Papyrus is a thick paper-like material produced from the pith of the papyrus plant, Cyperus papyrus, a wetland sedge that was once abundant in the Nile Delta of Egypt....

manuscripts in late antiquity and then in early medieval vellum
Vellum
Vellum is mammal skin prepared for writing or printing on, to produce single pages, scrolls, codices or books. It is generally smooth and durable, although there are great variations depending on preparation, the quality of the skin and the type of animal used...

codices), the "lunate
Lunate
Lunate is a term meaning crescent or moon-shaped. In the specialized terminology of lithic reduction, a lunate flake is a small, crescent-shaped flake removed from a stone tool during the process of pressure flaking....

" shape became predominant. In cursive
Cursive
Cursive, also known as joined-up writing, joint writing, or running writing, is any style of handwriting in which the symbols of the language are written in a simplified and/or flowing manner, generally for the purpose of making writing easier or faster...

handwriting, a large number of shorthand glyphs came to be used, where the cross-bar and the curved stroke were linked in various ways. Some of them resembled a modern lowercase Latin "e", some a "6" with a connecting stroke to the next letter starting from the middle, and some a combination of two small "c"-like curves. Several of these shapes were later taken over into minuscule
Minuscule Greek
The minuscule script was a writing style in the history of Greek writing which was used as a book hand in Byzantine manuscripts since the 9th and 10th centuries. It replaced the earlier style of uncial writing, from which it differed in using smaller, more rounded and more connected letter forms,...

book hand. Of the various minuscule letter shapes, the inverted-3 form became the basis for lower-case Epsilon in Greek typography during the modern era.
Uncial Uncial variants Cursive variants Minuscule Minuscule with ligatures

### International Phonetic Alphabet

In the International Phonetic Alphabet
International Phonetic Alphabet
The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic...

, the Latin epsilon ɛ represents open-mid front unrounded vowel, as in the English word "pet" ˈpɛt.

### Symbol

The uppercase Epsilon is not commonly used outside of the Greek language because of its similarity to the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

letter E
E
E is the fifth letter and a vowel in the basic modern Latin alphabet. It is the most commonly used letter in the Czech, Danish, Dutch, English, French, German, Hungarian, Latin, Norwegian, Spanish, and Swedish languages.-History:...

.

#### Lower case

The Greek lowercase epsilon ε, the lunate epsilon symbol ϵ, or the Latin lowercase epsilon ɛ (see above) is used as the symbol for:
##### Math and science
• In mathematics (particularly calculus
Calculus
Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

), an arbitrarily small positive quantity is commonly denoted ε; see (ε, δ)-definition of limit.
• By analogy with this, the late mathematician Paul Erdős
Paul Erdos
Paul Erdős was a Hungarian mathematician. Erdős published more papers than any other mathematician in history, working with hundreds of collaborators. He worked on problems in combinatorics, graph theory, number theory, classical analysis, approximation theory, set theory, and probability theory...

also used the term "epsilons" to refer to children (Hoffman 1998, p. 4).
• In mathematics, Hilbert
David Hilbert
David Hilbert was a German mathematician. He is recognized as one of the most influential and universal mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas in many areas, including invariant theory and the axiomatization of...

introduced epsilon terms as an extension to first order logic; see epsilon calculus
Epsilon calculus
Hilbert's epsilon calculus is an extension of a formal language by the epsilon operator, where the epsilon operator substitutes for quantifiers in that language as a method leading to a proof of consistency for the extended formal language...

.
• In mathematics, the Levi-Civita symbol
Levi-Civita symbol
The Levi-Civita symbol, also called the permutation symbol, antisymmetric symbol, or alternating symbol, is a mathematical symbol used in particular in tensor calculus...

.
• In mathematics, to represent the dual number
Dual number
In linear algebra, the dual numbers extend the real numbers by adjoining one new element ε with the property ε2 = 0 . The collection of dual numbers forms a particular two-dimensional commutative unital associative algebra over the real numbers. Every dual number has the form z = a + bε with a and...

s: a + , with ε2 = 0 and ε ≠ 0.
• In mathematics, sometimes used to denote the Heaviside step function
Heaviside step function
The Heaviside step function, or the unit step function, usually denoted by H , is a discontinuous function whose value is zero for negative argument and one for positive argument....

.
• In set theory
Set theory
Set theory is the branch of mathematics that studies sets, which are collections of objects. Although any type of object can be collected into a set, set theory is applied most often to objects that are relevant to mathematics...

, the limit ordinal
Epsilon nought
In mathematics, the epsilon numbers are a collection of transfinite numbers whose defining property is that they are fixed points of an exponential map. Consequently, they are not reachable from 0 via a finite series of applications of the chosen exponential map and of "weaker" operations like...

of the sequence .
• In computing, the precision
Precision (computer science)
In computer science, precision of a numerical quantity is a measure of the detail in which the quantity is expressed. This is usually measured in bits, but sometimes in decimal digits. It is related to precision in mathematics, which describes the number of digits that are used to express a...

of a numeric data type and floating-point machine epsilon
Machine epsilon
Machine epsilon gives an upper bound on the relative error due to rounding in floating point arithmetic. This value characterizes computer arithmetic in the field of numerical analysis, and by extension in the subject of computational science...

.
• In computer science
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

, the empty string
Empty string
In computer science and formal language theory, the empty string is the unique string of length zero. It is denoted with λ or sometimes Λ or ε....

, though different writers use a variety of other symbols for the empty string as well, including the upper-case Greek letter lambda
Lambda
Lambda is the 11th letter of the Greek alphabet. In the system of Greek numerals lambda has a value of 30. Lambda is related to the Phoenician letter Lamed . Letters in other alphabets that stemmed from lambda include the Roman L and the Cyrillic letter El...

.
• In physics, the permittivity
Permittivity
In electromagnetism, absolute permittivity is the measure of the resistance that is encountered when forming an electric field in a medium. In other words, permittivity is a measure of how an electric field affects, and is affected by, a dielectric medium. The permittivity of a medium describes how...

of a medium.
• In physics and electronics, the emf
Electromotive force
In physics, electromotive force, emf , or electromotance refers to voltage generated by a battery or by the magnetic force according to Faraday's Law, which states that a time varying magnetic field will induce an electric current.It is important to note that the electromotive "force" is not a...

of a circuit
• In physics, the strain
Strain (materials science)
In continuum mechanics, the infinitesimal strain theory, sometimes called small deformation theory, small displacement theory, or small displacement-gradient theory, deals with infinitesimal deformations of a continuum body...

of a material (a ratio of extensions).
• In automata theory
Automata theory
In theoretical computer science, automata theory is the study of abstract machines and the computational problems that can be solved using these machines. These abstract machines are called automata...

, a transition that involves no shifting of an input symbol.
• In astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, the fifth-brightest star in a constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

(see Bayer designation
Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name...

).
• In astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, Epsilon is the name for Uranus' most distant and most visible ring.
• In chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

, the molar extinction coefficient of a chromophore
Chromophore
A chromophore is the part of a molecule responsible for its color. The color arises when a molecule absorbs certain wavelengths of visible light and transmits or reflects others. The chromophore is a region in the molecule where the energy difference between two different molecular orbitals falls...

.
• In economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

, ε refers to elasticity
Elasticity (economics)
In economics, elasticity is the measurement of how changing one economic variable affects others. For example:* "If I lower the price of my product, how much more will I sell?"* "If I raise the price, how much less will I sell?"...

.
• In statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....

, to refer to error terms
Errors and residuals in statistics
In statistics and optimization, statistical errors and residuals are two closely related and easily confused measures of the deviation of a sample from its "theoretical value"...

.
• In agriculture, to represent the "photosynthetic efficiency" of a particular plant or crop.

### Fictional names

• In Greek it is used for Epsilon Team
Epsilon Team
The Epsilon Team is, according to a conspiracy theory, a secret society of Greek engineers, academics, pilots, powerful businessmen and politicians...

.
• "The Epsilon Program" is a mysterious cult
Cult
The word cult in current popular usage usually refers to a group whose beliefs or practices are considered abnormal or bizarre. The word originally denoted a system of ritual practices...

in the video game Grand Theft Auto: San Andreas
Grand Theft Auto: San Andreas
Grand Theft Auto: San Andreas is a 2004 open world action video game developed by British games developer Rockstar North and published by Rockstar Games. It is the third 3D game in the Grand Theft Auto video game franchise, the fifth original console release and eighth game overall...

by Game Developer Rockstar North
Rockstar North
Rockstar North is a British video game developer based in Edinburgh, Scotland, best known for creating the Grand Theft Auto and Lemmings franchises in its earlier guise as DMA....

. This cult is thought to be based on Scientology
Scientology
Scientology is a body of beliefs and related practices created by science fiction and fantasy author L. Ron Hubbard , starting in 1952, as a successor to his earlier self-help system, Dianetics...

.
• Epsilon is the lowest of five social caste
Caste
Caste is an elaborate and complex social system that combines elements of endogamy, occupation, culture, social class, tribal affiliation and political power. It should not be confused with race or social class, e.g. members of different castes in one society may belong to the same race, as in India...

s in the Aldous Huxley
Aldous Huxley
Aldous Leonard Huxley was an English writer and one of the most prominent members of the famous Huxley family. Best known for his novels including Brave New World and a wide-ranging output of essays, Huxley also edited the magazine Oxford Poetry, and published short stories, poetry, travel...

novel Brave New World
Brave New World
Brave New World is Aldous Huxley's fifth novel, written in 1931 and published in 1932. Set in London of AD 2540 , the novel anticipates developments in reproductive technology and sleep-learning that combine to change society. The future society is an embodiment of the ideals that form the basis of...

.
• Epsilon-Eagle is the name of the protagonist in the Sega Mega Drive
Sega Mega Drive
The Sega Genesis is a fourth-generation video game console developed and produced by Sega. It was originally released in Japan in 1988 as , then in North America in 1989 as Sega Genesis, and in Europe, Australia and other PAL regions in 1990 as Mega Drive. The reason for the two names is that...

game Alien Soldier
Alien Soldier
is a side-scrolling run and gun video game developed by Treasure for the Sega Mega Drive. The game was released in Japan and Europe, but not in the US , but it can be rather expensive due to its rarity in either region...

.

### Other uses

• "Epsilon" is the name used by General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...

for the post-2003 Epsilon platform
GM Epsilon platform
Epsilon is General Motors' mid-size front-wheel drive automobile platform. The architecture was developed by Opel, and debuted in the 2002 Opel Vectra and 2003 Saab 9-3. Since this platform falls squarely in the center of the worldwide automobile market, GM plans to produce a great many Epsilon...

.
EPIC Racing is a racing team from Spain, and a division of Spanish company Epsilon Euskadi. The team's headquarters are located in Azkoitia . It is the only major motorsport team from the Basque Country,...

, a carmaker and EpsilonEuskadi LMP1 car.
• Barazi-Epsilon
Barazi-Epsilon
Barazi-Epsilon is a racing team owned by engineer Michel Lecomte and entrepreneur turned amateur racer Juan Barazi. The teams base is located in Le Mans...

, a manufacturer in the 2009 Superleague Formula season
2009 Superleague Formula season
The 2009 Superleague Formula season was the second Superleague Formula championship. The series has been rebranded "Superleague Formula by Sonangol" for this season and also 2010 with the Angolan oil company becoming the title sponsor...

for the Olympique Lyonnais
Olympique Lyonnais
Olympique Lyonnais is a French association football club based in Lyon. They play in France's highest football division, Ligue 1. The club was formed as Lyon Olympique Universitaire in 1899, according to many supporters and sport historians, but was nationally established as a club in 1950. The...

car.
• Hurricane Epsilon, a storm of the 2005 Atlantic hurricane season
2005 Atlantic hurricane season
The 2005 Atlantic hurricane season was the most active Atlantic hurricane season in recorded history, repeatedly shattering numerous records. The impact of the season was widespread and ruinous with an estimated 3,913 deaths and record damage of about \$159.2 billion...

.
• Epsilon TB-30 is a training aircraft made by Socata and used by the French, Portuguese, Senegalese and Togo airforces. Introduced in 1984 it provides basic and intermediate training, and has a 300 hp lycoming engine.
• Stars Epsilon Eridani
Epsilon Eridani
Epsilon Eridani is a star in the southern constellation Eridanus, along a declination 9.46° south of the celestial equator. This allows the star to be viewed from most of the Earth's surface. At a distance of 10.5 light years , it has an apparent magnitude of 3.73...

and 40 Epsilon.
• Epsilon is a multi-platform Emacs
Emacs
Emacs is a class of text editors, usually characterized by their extensibility. GNU Emacs has over 1,000 commands. It also allows the user to combine these commands into macros to automate work.Development began in the mid-1970s and continues actively...

-like programmer's text editor by Lugaru Software Ltd
• Epsilon is used in the "reverse cat-face" emoticon
Emoticon
An emoticon is a facial expression pictorially represented by punctuation and letters, usually to express a writer’s mood. Emoticons are often used to alert a responder to the tenor or temper of a statement, and can change and improve interpretation of plain text. The word is a portmanteau word...

.

## Unicode

Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

Sample Description Notes on usage
U+0395 Ε Greek capital letter epsilon Greek alphabet
Greek alphabet
The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...

: close-mid front unrounded vowel
Close-mid front unrounded vowel
The close-mid front unrounded vowel, or high-mid front unrounded vowel, is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ....

/e/; uppercase for U+03B5
U+03B5 ε Greek small letter epsilon lowercase for U+0395
U+03F5 ϵ Greek lunate epsilon symbol mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

U+03F6 ϶ Greek reversed lunate epsilon symbol mathematics
U+0045 E
E
E is the fifth letter and a vowel in the basic modern Latin alphabet. It is the most commonly used letter in the Czech, Danish, Dutch, English, French, German, Hungarian, Latin, Norwegian, Spanish, and Swedish languages.-History:...

Latin capital letter e Latin alphabet
Latin alphabet
The Latin alphabet, also called the Roman alphabet, is the most recognized alphabet used in the world today. It evolved from a western variety of the Greek alphabet called the Cumaean alphabet, which was adopted and modified by the Etruscans who ruled early Rome...

; uppercase for U+0065
U+0065 e Latin small letter e IPA
International Phonetic Alphabet
The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic...

: close-mid front unrounded vowel
Close-mid front unrounded vowel
The close-mid front unrounded vowel, or high-mid front unrounded vowel, is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ....

; lowercase for U+0045
U+018E Ǝ Latin capital letter reversed e Pan-Nigerian alphabet
Pan-Nigerian alphabet
The Pan-Nigerian alphabet is a set of 33 Latin letters standardized by the National Language Centre of Nigeria in the 1980s. It is intended to be sufficient to write all the languages of Nigeria without using digraphs.-History:...

; African reference alphabet
African reference alphabet
An African reference alphabet was first proposed in 1978 by a UNESCO-organized conference held in Niamey, Niger, and the proposed alphabet was revised in 1982...

; uppercase for U+01DD
U+018F Ə Latin capital letter schwa Latin Azerbaijani
Azerbaijani language
Azerbaijani or Azeri or Torki is a language belonging to the Turkic language family, spoken in southwestern Asia by the Azerbaijani people, primarily in Azerbaijan and northwestern Iran...

and Chechen
Chechen language
The Chechen language is spoken by more than 1.5 million people, mostly in Chechnya and by Chechen people elsewhere. It is a member of the Northeast Caucasian languages.-Classification:...

alphabets: near-open front unrounded vowel /æ/; Uniform Turkic Alphabet
Uniform Turkic Alphabet
The Uniform Turkic Alphabet was a Latin alphabet used by non-Slavic peoples of the USSR in the 1930s. The alphabet used ligatures from Jaŋalif as it was also a part of the uniform alphabet. The uniform alphabet utilized Latin ligatures, excluding "w." Some additional ligatures were also introduced...

; uppercase for U+0259
U+0190 Ɛ Latin capital letter open e Niger–Congo languages
Niger–Congo languages
The Niger–Congo languages constitute one of the world's major language families, and Africa's largest in terms of geographical area, number of speakers, and number of distinct languages. They may constitute the world's largest language family in terms of distinct languages, although this question...

; African reference alphabet; uppercase for U+025B
U+01DD ǝ Latin small letter turned e lowercase for U+018E
U+0258 ɘ Latin small letter reversed e IPA: close-mid central unrounded vowel
Close-mid central unrounded vowel
The close-mid central unrounded vowel, or high-mid central unrounded vowel, is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is . This is a reversed letter e, and should not be confused with the schwa or turned e ǝ...

U+0259 ə Latin small letter schwa IPA: mid central vowel; lowercase for U+018F
U+025B ɛ Latin small letter open e IPA: open-mid front unrounded vowel; lowercase for U+0190
U+025C ɜ Latin small letter reversed open e IPA: open-mid central unrounded vowel
U+0404 Є Cyrillic capital letter Ukrainian ye Ukrainian
Ukrainian language
Ukrainian is a language of the East Slavic subgroup of the Slavic languages. It is the official state language of Ukraine. Written Ukrainian uses a variant of the Cyrillic alphabet....

and Rusyn
Rusyn language
Rusyn , also known in English as Ruthenian, is an East Slavic language variety spoken by the Rusyns of Central Europe. Some linguists treat it as a distinct language and it has its own ISO 639-3 code; others treat it as a dialect of Ukrainian...

languages: /je/, or the iotated
Iotation
Iotation is a linguistic phenomenon very characteristic of the Slavic languages. It should not be confused with palatalization, which is an entirely different process....

vowel sound /e/ after a palatalized
Palatalization
In linguistics, palatalization , also palatization, may refer to two different processes by which a sound, usually a consonant, comes to be produced with the tongue in a position in the mouth near the palate....

consonant; uppercase for U+0454
U+0415 Е Cyrillic capital letter ye Belarusian
Belarusian language
The Belarusian language , sometimes referred to as White Russian or White Ruthenian, is the language of the Belarusian people...

and Russian
Russian language
Russian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...

languages: a palatalizing vowel; Bulgarian
Bulgarian language
Bulgarian is an Indo-European language, a member of the Slavic linguistic group.Bulgarian, along with the closely related Macedonian language, demonstrates several linguistic characteristics that set it apart from all other Slavic languages such as the elimination of case declension, the...

, Macedonian
Macedonian language
Macedonian is a South Slavic language spoken as a first language by approximately 2–3 million people principally in the region of Macedonia but also in the Macedonian diaspora...

, Serbian
Serbian language
Serbian is a form of Serbo-Croatian, a South Slavic language, spoken by Serbs in Serbia, Bosnia and Herzegovina, Montenegro, Croatia and neighbouring countries....

, and Ukrainian languages: close-mid front unrounded vowel /e/ or open-mid front unrounded vowel /ɛ/; uppercase for U+0435
U+042D Э Cyrillic capital letter e Belarusian and Russian languages: close-mid front unrounded vowel /e/ or open-mid front unrounded vowel /ɛ/; uppercase for U+044D
U+0435 е Cyrillic small letter ye lowercase for U+0415
U+044D э Cyrillic small letter e lowercase for U+042D
U+0454 є
Ukrainian Ye
Ukrainian Ye is a character of the Cyrillic script. It is considered as an individual letter of modern Ukrainian alphabet and as a variant form of Ye in modern Church Slavonic language...

Cyrillic small letter Ukrainian ye lowercase for U+0404
U+04D8 Ә Cyrillic capital letter schwa Bashkir
Bashkir language
The Bashkir language is a Turkic language, and is the language of the Bashkirs. It is co-official with Russian in the Republic of Bashkortostan.-Speakers:...

, Kalmyk
Kalmyk language
The Kalmyk language , or Russian Oirat, is the native speech of the Kalmyk people of the Republic of Kalmykia, a federal subject of the Russian Federation. In Russia, it is the normative form of the Oirat language , which belongs to the Mongolic language family...

, Kazakh
Kazakh language
Kazakh is a Turkic language which belongs to the Kipchak branch of the Turkic languages, closely related to Nogai and Karakalpak....

and Tatar
Tatar language
The Tatar language , or more specifically Kazan Tatar, is a Turkic language spoken by the Tatars of historical Kazan Khanate, including modern Tatarstan and Bashkiria...

(and formerly Azeri) languages: near-open front unrounded vowel /æ/; Dungan
Dungan language
The Dungan language is a Sinitic language spoken by the Dungan of Central Asia, an ethnic group related to the Hui people of China.-History:...

language: close-mid back unrounded vowel
Close-mid back unrounded vowel
The close-mid back unrounded vowel, or high-mid back unrounded vowel, is a type of vowel sound, used in some spoken languages. Its symbol in the International Phonetic Alphabet is , called "ram's horns"...

/ɤ/; Kurdish
Kurdish language
Kurdish is a dialect continuum spoken by the Kurds in western Asia. It is part of the Iranian branch of the Indo-Iranian group of Indo-European languages....

language: mid central vowel /ə/; Abkhaz
Abkhaz language
Abkhaz is a Northwest Caucasian language spoken mainly by the Abkhaz people. It is the official language of Abkhazia where around 100,000 people speak it. Furthermore, it is spoken by thousands of members of the Abkhazian diaspora in Turkey, Georgia's autonomous republic of Adjara, Syria, Jordan...

language: labialization of the preceding consonant /ʷ/; uppercase for U+04D9
U+04D9 ә Cyrillic small letter schwa lowercase for U+04D8
U+20AC euro sign currency
Currency
In economics, currency refers to a generally accepted medium of exchange. These are usually the coins and banknotes of a particular government, which comprise the physical aspects of a nation's money supply...

designator
U+212E estimated sign prepackaged goods within the EU
U+2203 there exists mathematics
U+2208 element of mathematics
U+2209 not an element of mathematics
U+220A small element of mathematics
U+220B contains as member mathematics
U+220C does not contain as member mathematics
U+220D small contains as member mathematics