What is "foclut"

Focluth was the name of an ancient forest in Ireland. Saint Patrick refers to Focluth in the autobiographical portion of his Confession:

...I heard the voices of those Irish who live near the woods of Focluth near the Western Sea. They called out to me with a single voice: "We beg you, holy boy, come here and walk among us!"

Because Patrick was a native of Roman Britain who was taken to Ireland as a slave, most modern scholarship assumes that Focluth was the site of his captivity.