It has been handed down by tradition that the family of Day originally came from Wales. This tradition is undoubtedly correct. In a book of Heraldry, containing the arms of William Day, B. D., Provost of Eton College and Dean of Windsor, confirmed by William Flower, Norroy, on the 21st of October, 1582, in the twenty-fourth year of the reign of Queen Elizabeth, he is said to be descended from the Dees of Wales, viz. being younger son of Richard Day, who was the son of Nicholas Day, the son of John Dee, (called by the English, Daye.) He was son of Morgan Dee, younger brother to Richard Dee, Welshman."
"DEE" signifying, it is said, dark or dingy, is the name of a small river in Wales, and was probably applied to some ancestor of the family, dwelling upon its banks, in order to distinguish him from others — ^just as Wickliffe took his name from the village in which he was born — and in time, the word Dee came to be written, according to its apparent sound, Daye or Day. This name, moreover, still prevails in Wales, and is there pronounced as in England and this country.