YuleyoudaoicibaDictYouDict[Yule 词源字典]
Yule: [OE] Old English gēol, the ancestor of modern English Yule, was originally the name of a pre-Christian mid-winter festival, but it later came to be applied to ‘Christmas’. It was related to Old Norse jól ‘mid-winter festival’ (possible source of English jolly), but where it ultimately came from is not known. It has been speculated that it may be descended from the Indo- European base *qwelo- ‘go round’ (source of English cycle and wheel), in which case it would denote etymologically the ‘turn’ of the year.
[Yule etymology, Yule origin, 英语词源]
yule (n.)youdaoicibaDictYouDict
Old English geol, geola "Christmas Day, Christmastide," from Old Norse jol (plural), a heathen feast, later taken over by Christianity, of unknown origin.

The Old English (Anglian) cognate giuli was the Anglo-Saxons' name for a two-month midwinter season corresponding to Roman December and January, a time of important feasts but not itself a festival. After conversion to Christianity it narrowed to mean "the 12-day feast of the Nativity" (which began Dec. 25), but was replaced by Christmas by 11c., except in the northeast (areas of Danish settlement), where it remained the usual word.

Revived 19c. by writers to mean "the Christmas of 'Merrie England.' " First direct reference to the Yule log is 17c. Old Norse jol seems to have been borrowed in Old French as jolif, hence Modern French joli "pretty, nice," originally "festive" (see jolly).