a helmet for protecting the head in the event of an accident, worn by motorcyclists, automobile racers, etc.
Origin of crash helmet
First recorded in 1915–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a padded helmet worn for motorcycling, flying, bobsleighing, etc, to protect the head in a crash
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