Gamma is a term used in various fields, but it often refers to a type of radiation called gamma rays. These rays are a form of electromagnetic radiation, similar to X-rays, but with much higher energy. They are produced by radioactive materials and certain cosmic events, making them important in fields like nuclear medicine and astrophysics. In finance, "gamma" describes the rate of change in an option's delta, which measures how much the price of an option changes when the price of the underlying asset changes. Understanding gamma helps traders manage risk and make informed decisions about their investments.