Ahearn

Many Irish surnames can be traced back to their Gaelic forms. The name Ahearn originally appeared in Gaelic as O hEachthigheirn or O hEachthigheirna, made up of the words "each" meaning "steed," and "thighearna," meaning "lord." This was first Anglicized O'Hagherin, which was later changed to O'Aherne before the prefix was eventually dropped.