Why is the ninth month called September?
also quarter-staff, 1540s (quarter-stroke "stroke with a quarterstaff" is attested from early 15c.), stout pole, six to eight feet long (six-and-a-half sometimes is given as the standard length), tipped with iron, formerly a weapon used by the English peasantry. From staff (n.). The quarter likely is in reference to its operation.
It was grasped by one hand in the middle, and by the other between the middle and the end. In the attack the latter hand shifted from one quarter of the staff to the other, giving the weapon a rapid circular motion, which brought the ends on the adversary at unexpected points. [Century Dictionary]
a staff of wood from 6 to 9 feet (about 2 to 3 m) long, used for attack and defense. It is probably the cudgel or sapling with which many legendary heroes are described as being armed. The quarterstaff attained great popularity in England during the Middle Ages. It was usually made of oak, the ends often being shod with iron, and it was held with both hands, the right hand grasping it one-quarter of the distance from the lower end (hence the name) and the left at about the middle. The staff was used as a foil, or practice substitute, for the long, two-handed sword of the period. In earlier times, it may also have been used as a practice weapon for the spear and pike