sound truck definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a truck or van with amplifiers, loudspeakers, etc., used on the streets for disseminating political statements or appeals, advertising announcements, etc.
sound truck definition by American Heritage Dictionary
A truck or other vehicle having one or more loudspeakers, usually situated on top, typically used for broadcasting political or commercial messages.