Sextinemar

Sextinemar is equal to \(f_{\underbrace{\psi(M_{M_{..._{M}}})}_{7 \quad M's}}(10)\) using the fast-growing hierarchy with fundamental sequences for collapsing α-weakly inaccesible cardinals. The term was coined by wiki user Denis Maksudov.

Etymology
The 3 parts of the name, "sexti", "in" and "emar", mean \(6\), the "in-" operation. So the full name indicates the ordinal index of the number.