Zettinemar

Zettinemar is equal to \(f_{\underbrace{\psi(M_{M_{..._{M}}})}_{10^{21}+1 \quad M's}}(10)\). The term was coined by Denis Maksudov

Etymology
The 3 parts of the name, "zetto", "in" and "emar", mean \(10^{21}\), the "in-" operation. So the full name indicates the ordinal index of the number.