Gamma
Gamma /ˈɡæmə/[1] (uppercase Γ, lowercase γ; Greek: γάμμα gámma) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop /ɡ/. In Modern Greek, this letter represents either a voiced velar fricative or a voiced palatal fricative.
Greek alphabet  



History  
Archaic local variants
Numerals


Use in other languages  


Related topics  


 
In the International Phonetic Alphabet and other modern Latinalphabet based phonetic notations, it represents the voiced velar fricative.
History
The Greek letter Gamma Γ is a grapheme derived from the Phoenician letter 𐤂 (gīml) which was rotated from the righttoleft script of Canaanite to accommodate the Greek language’s writing system of lefttoright. The Canaanite grapheme represented the /g/ phoneme in the Canaanite language, and as such is cognate with gimel ג of the Hebrew alphabet.
Based on its name, the letter has been interpreted as an abstract representation of a camel's neck,[2] but this has been criticized as contrived,[3] and it is more likely that the letter is derived from an Egyptian hieroglyph representing a club or throwing stick.[4]
In Archaic Greece, the shape of gamma was closer to a classical lambda (Λ), while lambda retained the Phoenician Lshape (𐌋).
Letters that arose from the Greek gamma include Etruscan (Old Italic) 𐌂, Roman C and G, Runic kaunan ᚲ, Gothic geuua 𐌲, the Coptic Ⲅ, and the Cyrillic letters Г and Ґ.[5]
Greek phoneme
The Ancient Greek /g/ phoneme was the voiced velar stop, continuing the reconstructed protoIndoEuropean *g, *ǵ.
The modern Greek phoneme represented by gamma is realized either as a voiced palatal fricative (/ʝ/) before a front vowel (/e/, /i/), or as a voiced velar fricative /ɣ/ in all other environments. Both in Ancient and in Modern Greek, before other velar consonants (κ, χ, ξ k, kh, ks), gamma represents a velar nasal /ŋ/. A double gamma γγ represents the sequence /ŋɡ/ (phonetically varying [ŋɡ~ɡ]) or /ŋɣ/.
Phonetic transcription
Lowercase Greek gamma is used in the Americanist phonetic notation and Uralic Phonetic Alphabet to indicate voiced consonants.
The gamma was also added to the Latin alphabet, as Latin gamma, in the following forms: majuscule Ɣ, minuscule ɣ, and superscript modifier letter ˠ.
In the International Phonetic Alphabet the minuscule letter is used to represent a voiced velar fricative and the superscript modifier letter is used to represent velarization. It is not to be confused with the character ɤ, which looks like a lowercase Latin gamma that lies above the baseline rather than crossing, and which represents the closemid back unrounded vowel. In certain nonstandard variations of the IPA, the uppercase form is used.
It is as a fullfledged majuscule and minuscule letter in the alphabets of some of languages of Africa such as Dagbani, Dinka, Kabye, and Ewe,[6] and Berber languages using the Berber Latin alphabet.
It is sometimes also used in the romanization of Pashto.
Mathematics and science
Lowercase
The lowercase letter is used as a symbol for:
 Chromatic number of in graph theory
 Gamma radiation in nuclear physics
 The photon, the elementary particle of light and other electromagnetic radiation
 Surface energy in materials science
 The Lorentz factor in the theory of relativity
 In mathematics, the lower incomplete gamma function
 The heat capacity ratio C_{p}/C_{v} in thermodynamics
 The activity coefficient in thermodynamics
 The gyromagnetic ratio in electromagnetism
 Gamma waves in neuroscience
 Gamma motor neurons in neuroscience
 A nonSI metric unit of measure of mass equal to one microgram (1 μg).[7] This alwaysrare use is currently deprecated.
 A nonSI unit of measure of magnetic flux density, sometimes used in geophysics, equal to 1 nanotesla (nT).
 The power by which the luminance of an image is increased in gamma correction
 The Euler–Mascheroni constant
 In civil and mechanical engineering:
 Specific weight
 The shear rate of a fluid is represented by a lowercase gamma with a dot above it:
 Austenite (also known as γiron), a metallic nonmagnetic allotrope or solid solution of iron.
 The gamma carbon, the third carbon attached to a functional group in organic chemistry and biochemistry; see Alpha and beta carbon
The lowercase Latin gamma ɣ can also be used in contexts (such as chemical or molecule nomenclature) where gamma must not be confused with the letter y, which can occur in some computer typefaces.
Uppercase
The uppercase letter is used as a symbol for:
 In mathematics, the gamma function (usually written as function) is an extension of the factorial to complex numbers
 In mathematics, the upper incomplete gamma function
 The Christoffel symbols in differential geometry
 In probability theory and statistics, the gamma distribution is a twoparameter family of continuous probability distributions.
 In solidstate physics, the center of the Brillouin zone
 Circulation in fluid mechanics
 As reflection coefficient in physics and electrical engineering
 The tape alphabet of a Turing machine
 The Feferman–Schütte ordinal
 One of the Greeks in mathematical finance
Encoding
HTML
The HTML entities for uppercase and lowercase gamma are Γ
and γ
.
Unicode
 Greek Gamma
Preview  Γ  γ  ᴦ  ᵞ  ᵧ  

Unicode name  GREEK CAPITAL LETTER GAMMA  GREEK SMALL LETTER GAMMA  GREEK LETTER SMALL CAPITAL GAMMA  MODIFIER LETTER SMALL GREEK GAMMA  GREEK SUBSCRIPT SMALL LETTER GAMMA  
Encodings  decimal  hex  decimal  hex  decimal  hex  decimal  hex  decimal  hex 
Unicode  915  U+0393  947  U+03B3  7462  U+1D26  7518  U+1D5E  7527  U+1D67 
UTF8  206 147  CE 93  206 179  CE B3  225 180 166  E1 B4 A6  225 181 158  E1 B5 9E  225 181 167  E1 B5 A7 
Numeric character reference  Γ  Γ  γ  γ  ᴦ  ᴦ  ᵞ  ᵞ  ᵧ  ᵧ 
Named character reference  Γ  γ 
 Coptic Gamma
Preview  Ⲅ  ⲅ  

Unicode name  COPTIC CAPITAL LETTER GAMMA  COPTIC SMALL LETTER GAMMA  
Encodings  decimal  hex  decimal  hex 
Unicode  11396  U+2C84  11397  U+2C85 
UTF8  226 178 132  E2 B2 84  226 178 133  E2 B2 85 
Numeric character reference  Ⲅ  Ⲅ  ⲅ  ⲅ 
 Latin Gamma / phonetic Gamma
Preview  Ɣ  ɣ  ˠ  ɤ  

Unicode name  LATIN CAPITAL LETTER GAMMA  LATIN SMALL LETTER GAMMA  MODIFIER LETTER SMALL GAMMA  LATIN SMALL LETTER RAMS HORN  
Encodings  decimal  hex  decimal  hex  decimal  hex  decimal  hex 
Unicode  404  U+0194  611  U+0263  736  U+02E0  612  U+0264 
UTF8  198 148  C6 94  201 163  C9 A3  203 160  CB A0  201 164  C9 A4 
Numeric character reference  Ɣ  Ɣ  ɣ  ɣ  ˠ  ˠ  ɤ  ɤ 
 CJK Square Gamma
Preview  ㌏  

Unicode name  SQUARE GAMMA  
Encodings  decimal  hex 
Unicode  13071  U+330F 
UTF8  227 140 143  E3 8C 8F 
Numeric character reference  ㌏  ㌏ 
 Technical / Mathematical Gamma
Preview  ℾ  ℽ  𝚪  𝛄  𝛤  𝛾  

Unicode name  DOUBLESTRUCK CAPITAL GAMMA  DOUBLESTRUCK SMALL GAMMA  MATHEMATICAL BOLD CAPITAL GAMMA  MATHEMATICAL BOLD SMALL GAMMA  MATHEMATICAL ITALIC CAPITAL GAMMA  MATHEMATICAL ITALIC SMALL GAMMA  
Encodings  decimal  hex  decimal  hex  decimal  hex  decimal  hex  decimal  hex  decimal  hex 
Unicode  8510  U+213E  8509  U+213D  120490  U+1D6AA  120516  U+1D6C4  120548  U+1D6E4  120574  U+1D6FE 
UTF8  226 132 190  E2 84 BE  226 132 189  E2 84 BD  240 157 154 170  F0 9D 9A AA  240 157 155 132  F0 9D 9B 84  240 157 155 164  F0 9D 9B A4  240 157 155 190  F0 9D 9B BE 
UTF16  8510  213E  8509  213D  55349 57002  D835 DEAA  55349 57028  D835 DEC4  55349 57060  D835 DEE4  55349 57086  D835 DEFE 
Numeric character reference  ℾ  ℾ  ℽ  ℽ  𝚪  𝚪  𝛄  𝛄  𝛤  𝛤  𝛾  𝛾 
Preview  𝜞  𝜸  𝝘  𝝲  𝞒  𝞬  

Unicode name  MATHEMATICAL BOLD ITALIC CAPITAL GAMMA  MATHEMATICAL BOLD ITALIC SMALL GAMMA  MATHEMATICAL SANSSERIF BOLD CAPITAL GAMMA  MATHEMATICAL SANSSERIF BOLD SMALL GAMMA  MATHEMATICAL SANSSERIF BOLD ITALIC CAPITAL GAMMA  MATHEMATICAL SANSSERIF BOLD ITALIC SMALL GAMMA  
Encodings  decimal  hex  decimal  hex  decimal  hex  decimal  hex  decimal  hex  decimal  hex 
Unicode  120606  U+1D71E  120632  U+1D738  120664  U+1D758  120690  U+1D772  120722  U+1D792  120748  U+1D7AC 
UTF8  240 157 156 158  F0 9D 9C 9E  240 157 156 184  F0 9D 9C B8  240 157 157 152  F0 9D 9D 98  240 157 157 178  F0 9D 9D B2  240 157 158 146  F0 9D 9E 92  240 157 158 172  F0 9D 9E AC 
UTF16  55349 57118  D835 DF1E  55349 57144  D835 DF38  55349 57176  D835 DF58  55349 57202  D835 DF72  55349 57234  D835 DF92  55349 57260  D835 DFAC 
Numeric character reference  𝜞  𝜞  𝜸  𝜸  𝝘  𝝘  𝝲  𝝲  𝞒  𝞒  𝞬  𝞬 
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.
See also
Look up Γ or γ in Wiktionary, the free dictionary. 
Look up Ɣ or ɣ in Wiktionary, the free dictionary. 
 Г, г  Ge (Cyrillic)
 G, g  Latin
 Gamma correction
References
 "gamma". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
 Russell, Bertrand (1972). A history of western philosophy (60th print. ed.). New York: Touchstone book. ISBN 9780671314002.
 Powell, Barry B. (2012). Writing: Theory and History of the Technology of Civilization. John Wiley & Sons. p. 182. ISBN 9781118293492.
 Hamilton, Gordon James (2006). The Origins of the West Semitic Alphabet in Egyptian Scripts. Catholic Biblical Association of America. pp. 53–6. ISBN 9780915170401.
 "Greek Alphabet Symbols". Rapid Tables. Retrieved 25 August 2014.
 Practical Orthography of African Languages
 François Cardarelli (2003). Encyclopaedia of Scientific Units, Weights and Measures. SpringerVerlag London Ltd. ISBN 9781447111221.