Gamma
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Look up Γ or γ in Wiktionary, the free dictionary. |
Gamma (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, gamma represented a voiced velar stop /ɡ/. In Modern Greek, it represents a voiced fricative.
Based on its phonetic value in Modern Greek, gamma has also been introduced in a number of modern Latin-alphabet based phonetic notations (Latin (or latinized) gamma Ɣ).
History
The Greek letter Gamma Γ was derived from the Phoenician letter for the /g/ phoneme (𐤂 gīml), and as such is cognate with Hebrew gimel ג. Based on its name, the letter has been interpreted as an abstract representation of a camel's neck,[1] but this has been criticized as contrived,[2] and it is more likely that the letter is derived from an Egyptian hieroglyph representing a club or throwing stick.[3]
In the archaic period, the shape of gamma was closer to a classical lambda (Λ), while lambda retained the Phoenician L-shape (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.[4]
Greek phoneme
The Ancient Greek /g/ phoneme was the voiced velar stop, continuing the PIE voiced velar and palatal stops *g, *ǵ.
The modern Greek phoneme represented by gamma is realized either as a palatal /ʝ/ (before a front vowel, /e, i/), or as a velar /ɣ/ (in all other environments). Both in Ancient and in Modern Greek, before other velars (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
Look up Ɣ or ɣ in Wiktionary, the free dictionary. |
Lowercase Greek gamma is used in the Americanist phonetic notation and Uralic Phonetic Alphabet to indicate voiced consonants. In International Phonetic Alphabet, it represents the voiced velar fricative.
In these contexts, gamma is considered as an addition to Latin alphabet, the so-called Latin or latinized gamma ɣ (with an upper-case variant Ɣ based on the minuscule).
Latin gamma is used to represent a voiced velar fricative, both in the International Phonetic Alphabet, and in the alphabets of African languages such as Dagbani, Dinka, Kabiyé, and Ewe,[5] some Berber languages using the Berber Latin alphabet, and sometimes in the romanization of Pashto.
Lowercase Latin gamma is used in the International Phonetic Alphabet to represent the voiced velar fricative. A lowercase Latin gamma that lies above the baseline rather than crossing it (ɤ) represents the close-mid back unrounded vowel. In certain nonstandard variations of the IPA the uppercase form is used.
Mathematics and science
Lower case
The lower-case 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 theory theory of relativity
- The heat capacity ratio Cp/Cv in thermodynamics
- The activity coefficient in thermodynamics
- The gyromagnetic ratio in electromagnetism
- Gamma waves in neuroscience
- Gamma motor neurons in neuroscience
- A non-SI metric unit of measure of mass equal to one microgram (1 μg).[6] This always-rare use is currently deprecated.
- A non-SI 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 mechanical engineering:
- Specific weight
- The shear rate of a fluid is represented by a lower case gamma with a dot above it:
- Austenite (also known as γ-iron), a metallic non-magnetic 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.
Upper case
The upper-case 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
- The Christoffel symbols in differential geometry
- In probability theory and statistics, the gamma distribution is a two-parameter family of continuous probability distributions.
- Circulation in fluid mechanics
- As reflection coefficient in physics and electrical engineering
- The tape alphabet of a Turing machine
- The Feferman–Schütte ordinal
Encoding
HTML
The HTML entities for uppercase and lowercase gamma are Γ
and γ
.
Unicode
- Greek Gamma
Character | 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 |
UTF-8 | 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
Character | Ⲅ | ⲅ | ||
---|---|---|---|---|
Unicode name | COPTIC CAPITAL LETTER GAMMA | COPTIC SMALL LETTER GAMMA | ||
Encodings | decimal | hex | decimal | hex |
Unicode | 11396 | U+2C84 | 11397 | U+2C85 |
UTF-8 | 226 178 132 | E2 B2 84 | 226 178 133 | E2 B2 85 |
Numeric character reference | Ⲅ | Ⲅ | ⲅ | ⲅ |
Character | 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 |
UTF-8 | 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 |
- Latin / phonetic Gamma
Character | 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 |
UTF-8 | 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
Character | ㌏ | |
---|---|---|
Unicode name | SQUARE GAMMA | |
Encodings | decimal | hex |
Unicode | 13071 | U+330F |
UTF-8 | 227 140 143 | E3 8C 8F |
Numeric character reference | ㌏ | ㌏ |
- Technical / Mathematical Gamma
Character | ℾ | ℽ | 𝚪 | 𝛄 | 𝛤 | 𝛾 | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Unicode name | DOUBLE-STRUCK CAPITAL GAMMA | DOUBLE-STRUCK 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 |
UTF-8 | 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 |
UTF-16 | 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 |
Character | 𝜞 | 𝜸 | 𝝘 | 𝝲 | 𝞒 | 𝞬 | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL BOLD ITALIC CAPITAL GAMMA | MATHEMATICAL BOLD ITALIC SMALL GAMMA | MATHEMATICAL SANS-SERIF BOLD CAPITAL GAMMA | MATHEMATICAL SANS-SERIF BOLD SMALL GAMMA | MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL GAMMA | MATHEMATICAL SANS-SERIF 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 |
UTF-8 | 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 |
UTF-16 | 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
References
- ↑ Russell, Bertrand (1972). A history of western philosophy (60th print. ed.). New York: Touchstone book. ISBN 9780671314002.
- ↑ Powell, Barry B. (27 March 2009). Writing: Theory and History of the Technology of Civilization. Wiley Blackwell. p. 182. ISBN 978-1405162562.
- ↑ Gordon James Hamilton, The Origins of the West Semitic Alphabet in Egyptian Scripts (2006), 53–56.
- ↑ "Greek Alphabet Symbols". Rapid Tables. Retrieved 25 August 2014.
- ↑ Practical Orthography of African Languages
- ↑ François Cardarelli (2003). Encyclopaedia of Scientific Units, Weights and Measures. Springer-Verlag London Ltd. ISBN 978-1-4471-1122-1.