What Greek letter is represented by 'Psi'?

The Greek letter represented by 'Psi' is Ψ, which is used in various contexts such as mathematics, physics, and psychology. It is the 23rd letter of the Greek alphabet and is often associated with concepts like wave functions in quantum mechanics and the study of psychological phenomena. The distinct shape of Ψ, which resembles a trident, helps in differentiating it from other Greek letters.

In contrast, the other options represent different Greek letters: Ω corresponds to 'Omega,' X does not accurately represent any Greek letter but sounds similar to the letter 'Chi,' and Π represents 'Pi.' Each of these letters serves different functions and meanings within their respective fields, further affirming that Ψ is the specific representation of the Greek letter for 'Psi.'