0 a group of people who take part in protests wearing black clothes and with their faces covered with scarves, masks, dark glasses, etc., and who are sometimes violent:
1 belonging or relating to a group of people who take part in protests wearing black clothes and with their faces covered with scarves, masks, dark glasses, etc., and who are sometimes violent:
Clothing was discovered that was throught to belong to the Black Bloc.
Protesters were converging and the black bloc would soon follow.
A black bloc is made up largely of anarchists or autonomists.
The Black Bloc strategy is simple: Show up at demonstrations and attack the prominent symbols of capitalism.