signal flare; fusee
A pyrotechnic device used for signaling, especially in railway or maritime contexts. The term is technical and not commonly used in everyday conversation.
Railway workers use signal flares in emergencies.
A signal flare emits a red flame to warn of danger.
Compound of 信号 (signal) + 炎 (flame) + 管 (tube). The term likely originated in railway or maritime safety contexts.