Translated from the Gaelic, Sionnagh (anglicized to Shinnick) means Fox.  Many more accepted the direct English translation,  especially in the case of families who were ancient Chiefs of Teffia.  There territory was called Munster Tadhgain which contained part of the baronies of Rathcontrath and Cioneonan in Westmeath and part of the barony of Kilourcy in Kings County.

Niall's father was Eochaidh Muigh-Medon, of the Celtic line of Erimhon, one of the sons of Esbain who took Ireland from the Tuatha de Danann. Niall's mother was Carthann Cas Dubh, daughter of the king of Britain. Niall's had at least twelve sons, one of whom was MAINE ancestor of the Shinnick/Fox line. Niall's ancestry can be traced back to Miledh of Esbain, King of Spain, whose wife was the daughter of the Egyptian Pharaoh Nectonibus. From there the line goes back fifteen generations to Niul (from whom the river Nile got its name) . As High King of Ireland, Niall reigned from the ancient Irish royal seat at Tara, in modern Co. Meath. During his reign he conquered all of Ireland and Scotland and much of Britain and Wales. He took a royal hostage from each of the nine kingdoms he subjugated, hence his famous nickname.

The Shinnick name did not appear in New England until the 1840's .  One of the best known was Rev. William Shinnick pastor for more than 25 years of the Catholic church in Marblehead, MA