What is the X in X-mas?
masc. proper name, from Old English Hunfrið, probably from Proto-Germanic *hun "strength" + Old English frið "peace." To dine with Duke Humphrey (17c.) meant to go without a meal, though the reason for the expression now is obscure.
English county, Old English Gleawceaster, from Latin Coloniae Glev (2c.), from Glevo, a Celtic name meaning "bright place" (perhaps influenced by Old English gleaw "wise, prudent") + Old English ceaster "Roman town" (see Chester).