sigmapi

Sigmapi is a Greek letter, specifically the 18th letter of the Greek alphabet. It is a variant of the letter Pi (π), with a horizontal bar through its middle. The symbol is used in various contexts, including mathematics, physics, and engineering. In mathematics, sigmapi (Σ) is used to represent summation, indicating the sum of a sequence of numbers. In physics, it can denote the surface tension or the total energy of a system. In engineering, it may represent the stress or the total force. The letter is also used in the naming of organizations, such as Sigma Pi, a social fraternity for men. Despite its variant form, sigmapi retains the numerical value of 160 in the Greek numeral system.