also: せっき
A literal red-colored flag, often used as a warning signal or symbol of revolution.
A red flag was being waved at the construction site.
Proper noun: the official newspaper of the Japanese Communist Party.
He reads the Red Flag every morning.
They put up a red flag at the construction site to warn of danger.
The demonstrators marched while waving red flags.
An accident occurred, the red flag was raised, and the race was suspended.