Gamma (uppercase γ, lowercase γ) is the third Greek letter.

Use of uppercase γ:

The gamma function of mathematics is related to factorial.

Gamma distribution of probability and statistics.

Electrical physical reflection coefficient.

Use of lowercase γ:

Euler constant of mathematics.

Financial mathematics risk management index.

One of the basic particles in physics: photon.

Gamma rays in physics and astronomy.

Lorentz factor in relativity and astronomy.

In physics, the adiabatic index of gas is sometimes expressed by κ.

г in Cyrillic letters and C and G in Latin letters are all derived from Gamma.