UK and ANZ, US usually nightstick, baton, US also billy (club) [noun] [C] - a short thick stick which police officers use in dangerous or threatening situations to hit other peopleThe police broke up the demonstration with tear gas and truncheons.Most British police officers are only armed with truncheons.
TRUNCHEON
Meaning of TRUNCHEON in English
Cambridge English vocab. Кембриджский английский словарь. 2012