Also called (in Britain and certain other countries): loudspeaker van
sound truck in American English
US
a truck or van with amplifiers, loudspeakers, etc., used on the streets for disseminating political statements or appeals, advertising announcements, etc.
Examples of 'sound truck' in a sentence
sound truck
`If I didn't," smiled Jon, `you'd rent a sound truck and broadcast it.
Maupin, Armistead FURTHER TALES OF THE CITY (1989)