Gamma

Template:Short description Template:Distinguish Template:About Template:Pp-semi-indef Template:More citations needed Template:Greek Alphabet

Gamma (Template:IPAc-en;<ref>Template:OED</ref> uppercase Template:Script, lowercase Template:Script; Template:Langx) 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 Template:IPA. In Modern Greek, this letter normally represents a voiced velar fricative Template:IPA, except before either of the two front vowels (/e/, /i/), where it represents a voiced palatal fricative Template:IPA; while /g/ in foreign words is instead commonly transcribed as γκ).

In the International Phonetic Alphabet and other modern Latin-alphabet based phonetic notations, it represents the voiced velar fricative.

History

Template:Further The Greek letter Gamma Γ is a grapheme derived from the Phoenician letter Template:Script (gīml) which was rotated from the right-to-left script of Canaanite to accommodate the Greek language's writing system of left-to-right. 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,<ref>Template:Cite book</ref> but this has been criticized as contrived,<ref>Template:Cite book</ref> and it is more likely that the letter is derived from an Egyptian hieroglyph representing a club or throwing stick.<ref>Template:Cite book</ref>

File:NAMA Alphabet grec.jpg

The alphabet on black-figure pottery with a lambda-shaped gamma

In Archaic Greece, the shape of gamma was closer to a classical lambda (Λ), while lambda retained the Phoenician L-shape (Template:Script).

Letters that arose from the Greek gamma include Etruscan (Old Italic) 𐌂, Roman C and G, Runic kaunan Template:Script, Gothic geuua Template:Script, the Coptic Ⲅ, and the Cyrillic letters Г and Ґ.<ref name="rapidtables">Template:Cite web</ref>

Greek phoneme

Template:Further

The Ancient Greek /g/ phoneme was the voiced velar stop, continuing the reconstructed proto-Indo-European *g, *ǵ.

The modern Greek phoneme represented by gamma is realized either as a voiced palatal fricative (Template:IPA) before a front vowel (/e/, /i/), or as a voiced velar fricative Template:IPA in all other environments. Both in Ancient and in Modern Greek, before other velar consonants (κ, χ, ξ – that is, k, kh, ks), gamma represents a velar nasal Template:IPA. A double gamma γγ (e.g., άγγελος, "angel") represents the sequence Template:IPA (phonetically varying Template:IPA) or Template:IPA.

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 Template:IPA, which looks like a lowercase Latin gamma that lies above the baseline rather than crossing, and which represents the close-mid back unrounded vowel. In certain nonstandard variations of the IPA, the uppercase form is used.Template:Citation needed

It is as a full-fledged majuscule and minuscule letter in the alphabets of some of languages of Africa such as Dagbani, Dinka, Kabye, and Ewe,<ref>Practical Orthography of African Languages</ref> 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 <math>\gamma</math> is used as a symbol for:

Chromatic number of in graph theory
Gamma radiation in nuclear physics
Shear strain in physics<ref>Template:Citation</ref>
Surface tension in physics<ref>Template:Citation</ref>
The photon, the elementary particle of light and other electromagnetic radiation
The 434 nm spectral line in the Balmer series<ref>Template:Cite web</ref>
Surface energy in materials science
The Lorentz factor in the theory of relativity<ref>Template:Cite book</ref>
In mathematics, the lower incomplete gamma function<ref>Template:Cite web</ref>
The heat capacity ratio Template:Math 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).<ref>Template:Cite book</ref><ref>Template:Cite book</ref> This always-rare use is deprecated.
A non-SI unit of measure of magnetic flux density, sometimes used in geophysics, equal to 10⁻⁵ gauss (G), or 1 nano tesla (nT).<ref>Template:Cite web</ref>
The power by which the luminance of an image is increased in gamma correction
In civil and mechanical engineering:
- Specific weight
- The shear rate of a fluid is represented by a lowercase gamma with a dot above it: <math> \dot \gamma </math>
- 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
Hermite constant<ref>Template:Cite web</ref>
The Euler’s Constant also known as Euler–Mascheroni constant ≈ 0.57721566490153286<ref>Template:Cite web</ref><ref>Template:Cite web</ref>
Stieltjes constants<ref>Template:Cite web</ref>
Chvátal–Sankoff constants

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 <math>\Gamma</math> is used as a symbol for:

In mathematics, the gamma function (usually written as <math>\Gamma</math>-function) is an extension of the factorial to complex numbers<ref>Template:Cite web</ref><ref>Template:Cite web</ref>
In mathematics, the upper incomplete gamma function<ref>Template:Cite web</ref>
The Christoffel symbols in differential geometry<ref>Template:Cite book</ref><ref>Template:Cite web</ref>
In probability theory and statistics, the gamma distribution is a two-parameter family of continuous probability distributions.<ref>Template:Cite web</ref>
In solid-state physics, the center of the Brillouin zone
Circulation in fluid mechanics
As reflection coefficient in physics and electrical engineering<ref>Template:Cite book</ref>
The tape alphabet of a Turing machine<ref>Template:Cite book</ref>
The Feferman–Schütte ordinal <math>\Gamma_0</math><ref>Template:Cite book</ref>
Congruence subgroups of the modular group of other arithmetic groups
One of the Greeks in mathematical finance

Unicode

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References

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