Gamma

Greek letters
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;
Greek alphabet

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 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.