What is "cethlenn"

In Irish mythology, Cethlenn ( Old Irish), Cethleann ( Modern Irish, or Cethlenn of the Crooked Teeth) was the wife of Balor of the Fomorians and, by him, the mother of Ethniu. She was also a prophetess and warned Balor of his impending defeat by the Tuatha Dé Danann in the second battle of Magh Tuiredh. During that battle she wounded the Dagda.

The town of Enniskillen ( Irish inis Cethlinn, "Cethlenn's island") in County Fermanagh, Northern Ireland is named after her.