TYMNESSOS

As already has been explained,

-ESSOS = -ETI

So, TYMNESSOS which is an ancient Lycian city, in fact is TUMNETI.

In its turn, TUMNETI surely has something to do with the word TUM(A)NI, meaning 'ten roubles' (Rayfield) and producing a TUMNIANI adjective. The word TUMNI is clearly an Old Kartvelian plural form of TUMI, which means something that might not survived until today.