A baton or truncheon (nightstick in American English) is essentially a stick of less than arms-length, usually made wood, plastic, or metal, and carried by law enforcement, correctional, and security personnel for non-lethal self-defense or combat situations. It is used to strike, poke, and lock onto body parts of an assailant.
There are several variations; but all are either gripped at one end (nightstick), or on a handle protruding at a right-angle near one end (based on the martial arts' tonfa).
At the end of the 20th century, a popular straight baton was made of steel tubing which collapsed together for carrying, then slid apart to extend. A small metal knob on the end added weight when the baton was used as a bludgeon.
British police officers traditionally carried simple wooden truncheons (in police slang simply called a "stick") instead of guns. In recent years they have been all but replaced by more modern side-arm and telescopic batons.
Orchestral conductorss use light-weight batons for direction rather than combat.
Relay racers carry (and pass on) symbolic batons.
Compare mace and staff of office for the marrying of defense and symbolism.