Psi

This is the last letter in the Greek alphabet.

Psi is written as ψ. It is the sound "ps" as in "lips." It is transliterated as "ps."

There are four consonants in the Greek alphabet that produce a double sound. They are θ (th), φ (ph), χ (ch), and ψ (ps).

Interesting: Some people like to pronounce χ as xsi. In this case, χ would be a fifth double sound.