from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
BACHELOR. The first degree taken at the universities in the arts and
sciences, as bachelor of arts, & c. It is called, in Latin, Baccalaureus,
from bacalus, or bacillus, a staff, because a staff was given, by way of
distinction, into the hands of those who had completed their studies. Some,
however, have derived the word from baccalaura, others from bas chevalier,
as designating young squires who aspire to the knighthood. (Dupin.) But the
derivation. of the word is uncertain.