I'm told it's the original Irish spelling of the modern name Dalny. But I'm wondering if the original was pronounced differently than Dalny? (Which I've heard pronounced like DAL-knee, DAL like Pal.)
For background,Dealgnaid was the wife of Partholon, who (it's said) led the second group of people to settle in Ireland, and the first group following Noah's flood. Partholon was from somewhere in the Mediterranean, according to some sources, and Dealgnaid is sometimes called the Daughter of Pharoah, but we're talking Biblical Days of Old here, so who knows. Anyway, Dealgnaid is clearly an Irish name.