What is the X in X-mas?
Old English norðsæ, usually meaning "the Bristol Channel." The application to the body of water presently so named (late 13c.) is from Dutch (Noordzee, Middle Dutch Noortzee); it lies to the north of Holland, where it was contrasted with the inland Zuider Zee, literally "Southern Sea"). To the Danes, it sometimes was Vesterhavet "West Sea." In English, this had been typically called the "German Sea" or "German Ocean," which follows the Roman name for it, Oceanus Germanicus. "German" persisted on some British maps at least into the 1830s.