Sextitar

Sextitar is equal to \(Tar(6)=f_{\underbrace{C(C(\cdots(C(C(\Omega_{6}2,0),0),\cdots ),0)}_{6\text{ C's}}}(6)\) using the fast-growing hierarchy with fundamental sequences for Taranovsky's notation. The term was coined by wiki user Denis Maksudov.

Etymology
The 2 parts of the name, "sexti" and "tar", mean \(6\) and Tar function (from Taranovsky's notation) respectively, which form \(Tar(6)\) when concatenated backwards. So the full name indicates how the number is constructed.