The letter "β" (beta) is the second letter of the Greek alphabet. It is used in both uppercase (Β) and lowercase (β) forms. In the Greek numeral system, beta has a value of 2. The letter is often associated with various scientific and mathematical concepts, such as beta decay in physics and beta coefficients in statistics. In addition to its numerical significance, beta is commonly used in various fields, including finance, where it measures the volatility of an asset compared to the market. The letter also appears in the names of several beta versions of software, indicating that they are in a testing phase before final release.