1500s, earlier haliday (c.1200), from Old English haligdæg "holy day; Sabbath," from halig "holy" (see holy) + dæg "day" (see day); in 14c. meaning both "religious festival" and "day of recreation," but pronunciation and sense diverged 16c. As a verb meaning "to pass the holidays" by 1869. Happy holidays is from mid-19c., in British English, with reference to summer vacation from school. As a Christmastime greeting, by 1937, American English, in Camel cigarette ads.