Gamma (letter)

Greek alphabet
Α α Alpha	Β β Beta
Γ γ Gamma	Δ δ Delta
Ε ε Epsilon	Ϝ ϝ Digamma
Ζ ζ Zeta	Η η Eta
Θ θ Theta	Ι ι Iota
Κ κ Kappa	Λ λ Lambda
Μ μ Mu	Ν ν Nu
Ξ ξ Xi	Ο ο Omicron
Π π Pi	Ϻ ϻ San
Ϙ ϙ Qoppa	Ρ ρ Rho
Σ σ Sigma	Τ τ Tau
Υ υ Upsilon	Φ φ Phi
Χ χ Chi	Ψ ψ Psi
Ω ω Omega	Ϡ ϡ Sampi

Gamma (upper case Γ, lower case γ) is the 3rd letter of the Greek alphabet. In the system of Greek numerals it has a value of 3.

It gives its name to several things:

• Gamma characteristic power law, and gamma correction in television and computer display systems. Gamma is the exponent in a power-law relationship between video or pixel values and the displayed brightness.
• In the game of Tetris, gamma is another name for the J tetromino.

The upper-case letter Γ is used as the symbol for:

• The gamma function (related to factorials) in mathematics.
• The Gamma distribution in probability theory and statistics.

• The reflection coefficient in electrical engineering.

The lower-case letter γ is used as the symbol for:

• The Euler-Mascheroni constant in mathematics.
• The photon, seen as an elementary particle in physics.
• Gamma rays in physics and astronomy.
• The gamma factor in relativity theory and astronomy.
• The adiabatic index of a gas in physics. Often the letter kappa κ is used.

Letters that arose from Gamma are the Roman C and G and the Cyrillic letter Ghe.