Tiernan Family History
Tiernan Name Meaning
Irish (Westmeath and Mayo): reduced Anglicized form of Gaelic Ó Tíghearnáin ‘descendant of Tíghearnán’, a diminutive of Tighearna, a byname meaning ‘lord’, ‘master’. Compare Tierney, McKiernan. Woulfe believes Ó Tíghearnáin to be a variant of Ó Tíghearnaigh (see Tierney) in both counties.
Source: Dictionary of American Family Names ©2013, Oxford University Press