bachelor (n.)youdaoicibaDictYouDict[bachelor 词源字典]
c. 1300, "young man;" also "youthful knight, novice in arms," from Old French bacheler, bachelor, bachelier (11c.) "knight bachelor," a young squire in training for knighthood, also "young man; unmarried man," and as a university title, of uncertain origin, perhaps from Medieval Latin baccalarius "vassal farmer, adult serf without a landholding," one who helps or tends a baccalaria "field or land in the lord's demesne" (according to old French sources, perhaps from an alteration of vacca "a cow" and originally "grazing land" [Kitchin]). Or from Latin baculum "a stick," because the squire would practice with a staff, not a sword. "Perhaps several independent words have become confused in form" [Century Dictionary]. Meaning in English expanded early 14c. to "young unmarried man," late 14c. to "one who has taken the lowest degree in a university." Bachelor party as a pre-wedding ritual is from 1882.[bachelor etymology, bachelor origin, 英语词源]
fee (n.)youdaoicibaDictYouDict
Middle English, representing the merger or mutual influence of two words, one from Old English, one from an Old French form of the same Germanic word, and both ultimately from a PIE root meaning "cattle."

The Old English word is feoh "livestock, cattle; movable property; possessions in livestock, goods, or money; riches, treasure, wealth; money as a medium of exchange or payment," from Proto-Germanic *fehu- (cognates: Old Saxon fehu, Old High German fihu, German Vieh "cattle," Gothic faihu "money, fortune"). This is from PIE *peku- "cattle" (cognates: Sanskrit pasu, Lithuanian pekus "cattle;" Latin pecu "cattle," pecunia "money, property").

The other word is Anglo-French fee, from Old French fieu, a variant of fief "possession, holding, domain; feudal duties, payment" (see fief), which apparently is a Germanic compound in which the first element is cognate with Old English feoh.

Via Anglo-French come the legal senses "estate in land or tenements held on condition of feudal homage; land, property, possession" (c. 1300). Hence fee-simple (late 14c.) "absolute ownership," as opposed to fee-tail (early 15c.) "entailed ownership," inheritance limited to some particular class of heirs (second element from Old French taillir "to cut, to limit").

The feudal sense was extended from landholdings to inheritable offices of service to a feudal lord (late 14c.; in Anglo-French late 13c.), for example forester of fe "a forester by heritable right." As these often were offices of profit, the word came to be used for "remuneration for service in office" (late 14c.), hence, "payment for (any kind of) work or services" (late 14c.). From late 14c. as "a sum paid for a privilege" (originally admission to a guild); early 15c. as "money payment or charge exacted for a license, etc."