According to the early Welsh genealogies, the mother of Ceredig son of Cunedda (in a later source called the mother of Cunedda) was named Gwawl. She was supposedly a daughter of Coel Hen of the North, a common progenitor of early princely lines. Although some have disagreed, Coel himself is likely a eponym created for the Kyle region of South Ayrshire in southern Scotland.
Gwawl is though to mean (GPC) 'light, brightness, radiance, splendour; bright'. This would be a very pretty name for a woman, and an especially apt one for a queen. Unfortunately, there is a another word in Welsh spelled exactly the same which leads us to a different conclusion regarding Ceredig's mother. Here is a page from P.C. Bartram's A CLASSICAL WELSH DICTIONARY:
Gwawl is 'wall' in Welsh. For Gwawl son of Clud (Clud being an eponym for the Clyde), it designates the Antonine Wall. As Cunedda was wrongly said to have come from Manau Gododdin, a region which stretched to both sides of the same Roman defensive barrier, it seems pretty obvious to me that Gwawl was chosen as the name of Ceredig's mother for exactly this reason, i.e he and his father were said to have originated or were "born" from the eastern end of the Antonine Wall.
MELERI, WIFE OF CEREDIG SON OF CUNEDDA
According to Dr. Simon Rodway of the University of Wales, Meleri is a hypocoristic form of Eleri. 'My', which means the same as our word my, is affixed to the front of the name as a term of endearment, viz. 'My Eleri.' Eleri itself is a Welsh form of the Latin name Hilarius, from hilaris, 'cheerful, merry.'
Meleri is one of the many daughters of Brychan, the eponymous IRISH founder of the kingdom of Brycheiniog. which lay to the southeast of Ceredigion.
CHILDREN OF CEREDIG AND MELERI
Of the progeny of Ceredig, we can do nothing better than cite Bartram once again:
To me the most interesting person here is the daughter Gwawr, mother of Gwynllyw. In a previous post (http://mistshadows.blogspot.com/2016/09/a-curious-coincidence-of-meaning.html), I discussed the Coedkernyw in Gwynllwg, a petty kingdom named for Gwynllyw, as well as the Celliwig located in the same vicinity. Arthur in Welsh tradition is always strongly associated with a Kernyw and also with a Celliwig. Gwynllwg was near Caerleon, the site of the City of the Legion where Arthur fought a battle according to the Historia Brittonum, and not far from the trajectus or Tribruit across the Severn where he fought another.
The son Carannog also plays into the story of Arthur, albeit more directly. He is the saint of that name from the Vita: