juggleryoudaoicibaDictYouDict[juggler 词源字典]
juggler: [12] A juggler was originally a ‘jester’, and the word is related to English joke. Its ultimate source was Latin joculātor, a derivative of jocus ‘jest’ (from which English gets joke). This passed into Old French as jogleor, and was borrowed into English at the beginning of the 12th century. It denoted a general entertainer or buffoon, but it was also used for a magician or conjurer, and it was presumably an underlying notion of dexterity or sleight of hand that led by the 17th century to its being used for someone who keeps several objects in the air at the same time.

Old French jogleor became modern French jougleur, and this spawned the variant form jongleur, which was borrowed into English in the 18th century.
=> jocular, joke[juggler etymology, juggler origin, 英语词源]
juggler (n.)youdaoicibaDictYouDict
c. 1100, iugulere "jester, buffoon," also "wizard, sorcerer," from Old English geogelere "magician, conjurer," also from Anglo-French jogelour, Old French jogleor (accusative), from Latin ioculatorem (nominative ioculator) "joker," from ioculari "to joke, to jest" (see jocular). Connecting notion between "magician" and "juggler" is dexterity.