Γ

Gamma in a capital letter Etymologicum Magnum (1499).

Gamma(in capital Interpreterin lowercase γ; call in ancient Greek γάμαgámma/.ám.ma/, in modern Greek γάμ(μ)αgám(m)a/ diagnosis.ma/) is the third letter of the Greek alphabet. Deriva de la letra gaml (of the Phoenician. In modern Greek, it is pronounced as a fricative to watch sound [ɣ] or as a fricative sound palatal [.]. In ancient Greek, it was pronounced as occlusive to watch sound [.]. In both ancient and modern Greek, gamma is pronounced in front of watches (including the gamma itself, so a double gamma is pronounced in both variants of the language: γγγελος['angelos] messenger).

The Roman letters C and G and the Cyrillic letters Ge Г and Ghe Ґ come from the Greek gamma.

In the Greek numeral system it has a value of 3 (Γ΄).

History

The Greek letter gamma derives from the Phoenician letter for the phoneme /g/, 𐤂 gaml, and as such is cognate to the Hebrew gimel ג.

Based on its name's resemblance ("giml") to camel (e.g. Arabic جمل gml), the Phoenician letter has been interpreted as an abstract representation of a camel's neck but this has been criticized as contrived and lacking in evidence. It is now considered more likely that the Phoenician letter derives from an Egyptian hieroglyph representing a club or throwing stick.

In Archaic Greece, the shape of gamma was more like that of classical lambda (Λ), while lambda retained the Phoenician L-shape (𐌋).

Letters that arose from Greek gamma include Etruscan (Old Italic) 𐌂, Roman C, Kaunan runic ᚲ, Gothic geuua 𐌲, Coptic Ⲅ, and Cyrillic Г.

Epigraphic variants

In archaic epigraphic sources the following variants appear:

Use

In Greek

The Ancient Greek phoneme /g/ was a voiced velar plosive, continuing the reconstructed phonemes *g, *ǵ of Proto-Indo-European, such as the g in the word Spanish cat.

The Modern Greek phoneme represented by gamma is pronounced as a voiced velar fricative /ɣ/, like the g in "friend". However, when gamma precedes a previous vowel (/e/, /i/) it is pronounced as a voiced palatal fricative (/ʝ/), which would be equivalent to the y sound in «yesterday».

In both ancient and modern Greek, before the velar consonants: κ, χ, ξ, (k, kh, ks), the gamma represents a velar nasal /ŋ/. A double gamma γγ represents the sequence /ŋɡ/ (which varies phonetically [ŋɡ~ɡ]) or /ŋɣ/.

As a symbol

Gamma is often used to denote a variable in mathematics and physics. In some fields it has specific meanings.

• Gamma correction in photography, television and computer screens. Gamma is the exponent in a relationship between video values or pixels and the brightness shown. In photography is the slope of the curve of the density of the photographic film (log(opacity)) in front of the log of the exhibition (Hurter-Driffield curve), in the straight section of the characteristic curve.
• 1 gamma is a unit of magnetic flow density, 1 gamma = 10⁻⁹ tesla or 1 nanotesla.
• The cerebral Gamma waves are a type of brain waves that are around 40 Hz.
• In virology, in the context of the COVID-19 pandemic, the World Health Organization (WHO) designated Gamma as a variant of concern, a mutation of the SARS-CoV-2, virus that produces COVID-19 disease, found in November 2020 in Brazil.

Uppercase

The capital letter Γ is used as a symbol for:

• Gamma function (relative to factorials) in mathematics;
• Christoffel Symbols, related to vectors and tensors;
• Gamma distribution in theory of probability and statistics;
• The coefficient of reflection in the study of transmission lines, in electrical engineering.
• Superficial concentration of excess, in chemistry.
• Define the moment in a scheme of forces, in physics.

Lowercase

The lowercase letter γ is used as a symbol for:

• The constant of Euler-Mascheroni in mathematics.
• A measure of risk in financial mathematics.
• The photon, seen as an elemental particle in physics.
• Gamma rays in physics and astronomy.
• The gamma factor in the theory of relativity and astronomy.
• The coefficient of adiabatic dilation of a gas in physics. The letter kappa κ is often used.
• The constant propagation of an electromantic wave in electrical engineering and electromagnetic theory.
• The third brightest star in a constellation. (See Bayer nomenclature).
• The specific weight of a material.
• Surface tension in chemistry.
• Part of the F1 subunit of the ATP-sintetasa around which the other parts are located.

Video Games

• In the game of Tetris, gamma is another name that designates J tetrominó.
• The capital gamma (selector) is the symbol that appears in the Waluigi cap in contrast to the L of Luigi.
• In the EarthBound video game, the letter Gamma (together with other letters from the Greek alphabet) is used to classify the level of each PSI. It's the third level of PSI, after the beta.
• In Sonic Adventure is the key name of Dr. E-102 robot. Eggman
• In Megaman 3 is the name of the robot created by the dr Light and Wily, besides being the final head of the game

Unicode

• Greek

• Copt

• Latino

• CJK Square

• Maths