CORDELIA, or CORDULA, is a Kymric or Welsh name, and, according to Mr. Davies, who has made a exhaustive study of the subject, the name was originally Creirdyddlydd; this means "the token of the flowing tide", or "daughter of the sea", her father Lear or Llyr being "the sea"... (Girls' Christian Names, Swan, 1905).

... Mr. Davies explains Cordelia to have been originally Creirdyddlydd, the token of the overflowing, also called Creirwy, or the token of the egg.  Creir is a token, the sacred article on which a man makes oath, whence it came to mean either a relic or a jewel.  Creirdyddlydd might thus be the jewel of the sea, or the token of the flood.  At any rate, Creirdyddlydd or Creirwy is a creation of ancient Welsh poetry, once mythical, the daughter of the sea, Llyr or Llud, on which Geoffrey seized for his history.  Bronwen (q.v.), or white bosom, is either another daughter of Lyr, or else Creirdyddlydd under another name,... (History of Christian Names, Yonge, 1884)