Mu (the sound of m. Looks like u with an extended left or M as a capital)
Xi is the fourteenth letter of the Greek alphabet.
The Greek capital letter for Lamda is Λ.
The Greek capital letter for Phi is Φ.
The Greek capital letter for Delta is Δ.
The Greek capital letter for Omega is Ω.
The Greek capital letter for Theta is Θ.
The Greek capital letter for Psi is Ψ.
The Greek capital letter for Sigma is Σ.
The Greek capital letter for Gamma is Γ.
The Greek capital letter for Pi is Π.
The 19th Greek letter is Ξ (xi). It is equivalent to the English letter "X" and has a numerical value of 60 in the Greek alphabet.