Gamma

Look up Γ or γ in Wiktionary, the free dictionary.

Greek alphabet
Αα Alpha Νν Nu Ββ Beta Ξξ Xi Γγ Gamma Οο Omicron Δδ Delta Ππ Pi Εε Epsilon Ρρ Rho Ζζ Zeta Σσς Sigma Ηη Eta Ττ Tau Θθ Theta Υυ Upsilon Ιι Iota Φφ Phi Κκ Kappa Χχ Chi Λλ Lambda Ψψ Psi Μμ Mu Ωω Omega
History
Archaic local variants Diacritics Ligatures Numerals ϛ (6) ϟ (90) ϡ (900)
Use in other languages
Bactrian Coptic Albanian
Related topics
Use as scientific symbols
Book Category Commons

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. It was derived from the Phoenician letter Gimel . Letters that arose from gamma include the Roman C and G and the Cyrillic letters Г and Ґ.^[1]

Uses

Greek

The alphabet on a black figure vessel, with a Λ-shaped gamma

In Ancient Greek, gamma represented a voiced velar stop /ɡ/. In Modern Greek, it represents a voiced fricative. It 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/.

International Phonetic Alphabet

In the International Phonetic Alphabet, lowercase gamma (ɣ) represents the voiced velar fricative. A lowercase gamma that lies above the baseline rather than crossing it (ɤ) represents the close-mid back unrounded vowel.

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).^[2] 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

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
• 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 Γ₀

Meteorology

• Gamma was one of the names used in the 2005 Atlantic hurricane season as Tropical Storm Gamma.

Technical notes

HTML

The HTML entities for uppercase and lowercase gamma are Γ and γ.

Unicode

• Greek Gamma

• Coptic Gamma

• Latin / phonetic Gamma

• CJK Square Gamma

• Technical / Mathematical Gamma

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

• Г, г - Ge (Cyrillic)
• G, g - Latin

References