Derivation from the Irish Gaelic Mac Cú Uladh 'son of the hound of Ulster' is more probable. While Cú Uladh may allude to the legendary Irish figure Cú Chulainn, it was a common given name in medieval Ireland.
The most likely origin of the name is from the Irish Gaelic "Mac Cú Uladh," meaning "son of the hound of Ulster." While Cú Chulainn may be a reference to the legendary Irish figure, it was a common given name in medieval Ireland.