The
knob at the end of the
hilt of
European swords, whose original function was to stop the hand from slipping off the hilt. Later, by the
11th century, it was used as a
counterweight, bringing the
center of gravity closer to the
hilt and thus making the sword easier to
wield.
It could also be used as a forceful blunt object, exacting blows to the head, for example, which is why, beginning around the
16th century and still used today, the word
pummel (as in, "he pummeled him to the ground.") means to beat something forcefully and repetitively.