1250-1300;Middle Englishbacheler < Old French < Vulgar Latin*baccalār(is) farm hand; akin to Late Latinbaccalāria piece of land, orig. plural of *baccalārium dairy farm, equivalent to *baccālis of cows (bacca, variant of Latinvacca cow + -ālis-al1) + -ārium place
c.1300, "youthful knight, novice in arms," from O.Fr. bacheler (11c.) "knight bachelor," a young squire in training for knighthood, probably from M.L. baccalarius "vassal farmer," one who helps or tends a baccalaria "section of land." Or from L. baculum "a stick," since the squire would practice with a staff, not a sword. Meaning evolved 14c. from "knight in training" to "junior member of a guild or university" to "unmarried man" (late 14c.), an evolution that paralleled the word's development in French. Bachelor party is first recorded 1922.