riot shield

noun

a large oblong curved transparent shield used by police controlling crowds
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

Examples from the Web for riot shield

  • Morris told me that the firm is currently working with a Dutch riot-shield manufacturer to produce a riot-ready Mosquito.

    High-Tech Anti-Riot Gear|Sam Bungey|August 14, 2011|DAILY BEAST