Tabarna or labarna was a royal title used by the Hittites.
It was used from at least the 17th century BC until the end of the Hittite empire, except for the brief period from Suppiluliuma I to Muwatalli II.
It was in origin possibly a personal name, borne by the first two Hittite kings, Labarna I and Labarna II.
In that regard, it is comparable to the Latin title caesar.
[1][2] Ilya Yakubovich calls it "the single most discussed word of the Hittite lexicon".