What does represent?

In mathematics, especially in algebra, statistics, probability theory, set theory, computer science, linguistics, logic, economics, physics, engineering, genetics, and many other disciplines, the symbol π (lower case Greek letter pi) denotes the ratio between the circumference of any circle and its diameter in Euclidean geometry.[1] Its approximation, 3.14159 (exactly), also commonly written as approximately 3.14, was familiar to Archimedes of Syracuse at least 230 BCE.[2]