A cudgel is a short heavy stick, also known as a club, bludgeon, truncheon, baton or push stick.
A beating with a cudgel is called a cudgelling. Cudgels, due to their weight, are likely to cause severe, possibly permanant or fatal, injuries and are therefore more a kind of weapon than an instrument for corporal punishment.
As one of the simplest yet effective types of weapon that could be easily made from wood by anyone, cudgels were used, for example, by criminals such as robbers against their victims. But also good people often kept a cudgel within quick reach to defend themselves against robbers, or wild animals. The "cudgel in the sack" is recorded in one of Grimm's fairy tales: "If any one has done anything to injure thee, do but say, ‘Out of the sack, Cudgel!’ and the cudgel will leap forth among the people, and play such a dance on their backs that they will not be able to stir or move for a week, and it will not leave off until thou sayest, “Into the sack, Cudgel!”"
Today, truncheons are mainly used by the police, corrections, security, and (less often) military personnel.