a truck-mounted hose or pipe that shoots a jet of water through a nozzle at extremely high pressure, used especially in dispersing rioters or demonstrators.
Origin of water cannon
First recorded in 1965–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an apparatus for pumping water through a nozzle at high pressure, used in quelling riots
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012