1) Scottish clan 
A tiarna (Irish), or tighearna (Scottish), both from the Old Irish tigerna, is a lord in the Gaelic world and languages. An Ard Tiarna is a `high lord`, approximately equal in rank to a count or earl, although many of such higher rank still happen to prefer the title on its own. Tierney Is a modern version of the surname of `Tiarna` even thoug...